JP2015079925A - Method for manufacturing rare earth magnet - Google Patents

Method for manufacturing rare earth magnet Download PDF

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JP2015079925A
JP2015079925A JP2013217888A JP2013217888A JP2015079925A JP 2015079925 A JP2015079925 A JP 2015079925A JP 2013217888 A JP2013217888 A JP 2013217888A JP 2013217888 A JP2013217888 A JP 2013217888A JP 2015079925 A JP2015079925 A JP 2015079925A
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magnet
powder
rare earth
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麻子 渡▲辺▼
Asako Watanabe
麻子 渡▲辺▼
前田　徹
Toru Maeda
前田　　徹
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Sumitomo Electric Industries Ltd
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Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a rare earth magnet by which a rare earth magnet superior in magnetic property can be manufacture with good productivity.SOLUTION: A method for manufacturing a rare earth magnet comprises the steps of: preparing hydrogenated powder 30 composed of a hydrogenated alloy including a rare earth element hydrogen compound and an iron group element, and anisotropic magnet powder 20 including a rare earth element and having crystal magnetic anisotropy; producing a powder compact 100 by press-compacting a powder mixture 110 including the hydrogenated powder and the anisotropic magnet powder while applying a magnetic field thereto; and performing a dehydrogenation treatment on the powder compact to cause the recombination in the hydrogenated alloy and thus, manufacturing a magnet material 10 in which particles of the anisotropic magnet powder are bonded to each other by the recombined alloy.

Description

本発明は、永久磁石などに利用される希土類磁石を製造する希土類磁石の製造方法に関するものである。   The present invention relates to a method for producing a rare earth magnet for producing a rare earth magnet used for a permanent magnet or the like.

モータや発電機などに利用される永久磁石には、希土類磁石が広く利用されている。希土類磁石は、ネオジム（Ｎｄ）、鉄（Ｆｅ）、硼素（Ｂ）を含む合金を主体とするネオジム磁石が代表的である。従来のネオジム磁石として、原料の磁石用粉末を成形してから焼結した焼結磁石、磁石用粉末がエポキシ樹脂などの樹脂によって結合された樹脂ボンド磁石がある。樹脂ボンド磁石は、磁石用粉末とバインダとなる樹脂との混合物を磁場印加中で射出成形したり、磁場印加中で圧縮成形した後、樹脂を硬化するための熱処理を施したりすることで製造できることから、焼結磁石よりも形状の自由度が高い。この点で、樹脂ボンド磁石は、利用し易い。   Rare earth magnets are widely used as permanent magnets used in motors and generators. The rare earth magnet is typically a neodymium magnet mainly composed of an alloy containing neodymium (Nd), iron (Fe), and boron (B). As a conventional neodymium magnet, there are a sintered magnet obtained by forming and sintering a raw magnet powder, and a resin bonded magnet in which the magnet powder is bonded by a resin such as an epoxy resin. Resin-bonded magnets can be manufactured by injection-molding a mixture of magnet powder and binder resin while applying a magnetic field, or compression-molding while applying a magnetic field, and then applying a heat treatment to cure the resin. Therefore, the degree of freedom of shape is higher than that of sintered magnets. In this respect, the resin bonded magnet is easy to use.

樹脂ボンド磁石では、原料に、結晶磁気異方性を有する粉末（以下、この粉末を異方性磁石粉末と呼ぶことがある）を用いて、異方性磁石とすることがなされている（例えば、特許文献１参照）。異方性磁石は、結晶磁気異方性によって、磁気特性に優れる。特許文献１では、最大エネルギー積が高い樹脂ボンド磁石を開示している。   In resin-bonded magnets, a powder having crystal magnetic anisotropy (hereinafter, this powder may be referred to as anisotropic magnet powder) is used as a raw material to make an anisotropic magnet (for example, , See Patent Document 1). An anisotropic magnet has excellent magnetic properties due to magnetocrystalline anisotropy. Patent Document 1 discloses a resin bonded magnet having a high maximum energy product.

焼結磁石や樹脂ボンド磁石以外の希土類磁石として、特許文献２では、Ｎｄ−Ｆｅ−Ｂ系合金の粉末を水素化した水素化粉末を原料粉末とし、この原料粉末を圧縮成形した粉末成形体に脱水素処理を施した圧縮磁石（圧粉磁石）を開示している。   As rare earth magnets other than sintered magnets and resin-bonded magnets, in Patent Document 2, a hydrogenated powder obtained by hydrogenating a powder of an Nd—Fe—B alloy is used as a raw material powder, and a powder compact is obtained by compression-molding this raw material powder. A compression magnet (powder magnet) subjected to dehydrogenation treatment is disclosed.

特開平０９−２４６０２８号公報Japanese Patent Laid-Open No. 09-246028 特開２０１１−２３６４９８号公報JP2011-236498A

従来の樹脂ボンド磁石では、非磁性材料である樹脂を含むことで、磁石相（Ｎｄ−Ｆｅ−Ｂ系合金など）の含有割合が相対的に低い。そのため、異方性磁石粉末を用いていても、磁気特性の向上に限界がある。   In the conventional resin bonded magnet, the content ratio of the magnet phase (Nd—Fe—B alloy or the like) is relatively low by including a resin which is a nonmagnetic material. Therefore, even if anisotropic magnet powder is used, there is a limit in improving the magnetic properties.

そこで、本発明の目的の一つは、磁気特性に優れる希土類磁石を生産性よく製造することができる希土類磁石の製造方法を提供することにある。   Then, one of the objectives of this invention is providing the manufacturing method of the rare earth magnet which can manufacture the rare earth magnet excellent in a magnetic characteristic with sufficient productivity.

本発明の希土類磁石の製造方法は、以下の準備工程、成形工程、及び結合工程を備える。
（準備工程）希土類元素の水素化合物と鉄族元素とを含む水素化合金からなる水素化粉末と、希土類元素を含み、結晶磁気異方性を有する異方性磁石粉末とを準備する工程。
（成形工程）前記水素化粉末と前記異方性磁石粉末とを含む混合粉末を磁場印加中で圧縮成形して粉末成形体を得る工程。
（結合工程）前記粉末成形体に脱水素処理を施して、前記水素化合金を再結合して、この再結合合金によって前記異方性磁石粉末の粒子が結合された磁石素材を製造する工程。 The method for producing a rare earth magnet of the present invention includes the following preparation process, molding process, and bonding process.
(Preparation step) A step of preparing a hydrogenated powder made of a hydrogenated alloy containing a rare earth element hydrogen compound and an iron group element, and an anisotropic magnet powder containing the rare earth element and having magnetocrystalline anisotropy.
(Molding step) A step of obtaining a powder compact by compression molding a mixed powder containing the hydrogenated powder and the anisotropic magnet powder while applying a magnetic field.
(Bonding step) A step of producing a magnet material in which particles of the anisotropic magnet powder are bonded by re-bonding the hydrogenated alloy by dehydrogenating the powder compact and rebonding the hydrogenated alloy.

本発明の希土類磁石の製造方法は、磁気特性に優れる希土類磁石を生産性よく製造することができる。   The method for producing a rare earth magnet of the present invention can produce a rare earth magnet having excellent magnetic properties with high productivity.

実施形態の希土類磁石の製造方法を説明する工程説明図である。It is process explanatory drawing explaining the manufacturing method of the rare earth magnet of embodiment. 実施形態の希土類磁石の製造方法によって製造された希土類磁石の組織を示す模式図である。It is a schematic diagram which shows the structure | tissue of the rare earth magnet manufactured by the manufacturing method of the rare earth magnet of embodiment.

［本発明の実施の形態の説明］
結晶磁気異方性を有する異方性磁石粉末などの磁石用粉末は、一般に塑性加工性に劣ることから、樹脂ボンド磁石のように、磁石用粉末の粒子同士を結合するための結合材が必要である。本発明者らは、磁気特性の向上を目指し、樹脂といった非磁性材料の結合材ではなく、磁性材料（磁石相）であって塑性変形性に優れる結合材を検討した。その結果、（ａ）希土類元素の水素化合物と鉄族元素とが独立した相として存在する合金、即ち水素不均化状態の組織を有する合金は、塑性加工性に優れることから、異方性磁石粉末などの磁石用粉末の粒子同士を結合できる、（ｂ）結合後に脱水素処理を施して上記合金を再結合合金とすることで、Ｎｄ−Ｆｅ−Ｂ系合金などの磁石相からなる結合材とすることができる、との知見を得た。本発明は、上記知見に基づくものである。以下、最初に本発明の実施形態の内容を列記して説明する。 [Description of Embodiment of the Present Invention]
Magnet powders such as anisotropic magnet powders having crystalline magnetic anisotropy are generally inferior in plastic workability, so a binder for bonding particles of magnet powders is required like resin bonded magnets. It is. In order to improve the magnetic characteristics, the present inventors examined a binding material that is a magnetic material (magnet phase) and has excellent plastic deformability, not a binding material of a nonmagnetic material such as resin. As a result, (a) an alloy in which a rare earth element hydrogen compound and an iron group element exist as independent phases, that is, an alloy having a structure in a hydrogen disproportionation state is excellent in plastic workability. (B) A binder composed of a magnetic phase such as an Nd—Fe—B alloy by performing dehydrogenation after bonding to make the above alloy a rebonded alloy. And obtained the knowledge that. The present invention is based on the above findings. Hereinafter, the contents of the embodiment of the present invention will be listed and described first.

（１） 実施形態に係る希土類磁石の製造方法は、以下の準備工程、成形工程、及び結合工程を備える。
（準備工程）希土類元素の水素化合物と鉄族元素とを含む水素化合金からなる水素化粉末と、希土類元素を含み、結晶磁気異方性を有する異方性磁石粉末とを準備する工程。
（成形工程）上記水素化粉末と上記異方性磁石粉末とを含む混合粉末を磁場印加中で圧縮成形して粉末成形体を得る工程。
（結合工程）上記粉末成形体に脱水素処理を施して、上記水素化合金を再結合して、この再結合合金によって上記異方性磁石粉末の粒子が結合された磁石素材を製造する工程。 (1) The manufacturing method of the rare earth magnet according to the embodiment includes the following preparation process, molding process, and bonding process.
(Preparation step) A step of preparing a hydrogenated powder made of a hydrogenated alloy containing a rare earth element hydrogen compound and an iron group element, and an anisotropic magnet powder containing the rare earth element and having magnetocrystalline anisotropy.
(Molding step) A step of obtaining a powder molded body by compression molding a mixed powder containing the hydrogenated powder and the anisotropic magnet powder while applying a magnetic field.
(Bonding step) A step of producing a magnet material in which the anisotropic magnet powder particles are bonded by re-bonding the hydrogenated alloy by performing dehydrogenation treatment on the powder compact.

結晶磁化容易軸（代表的にはｃ軸）の配向度が高く、異方性に優れる磁石粉末は、一般に、残留磁束密度Ｂｒが高い。従って、上記「結晶磁気異方性を有する異方性磁石粉末」とは、残留磁束密度Ｂｒが１．０Ｔ以上を満たす磁石粉末とする。上記残留磁束密度Ｂｒの測定方法は、後述する。   Magnet powders having a high degree of orientation of the easy axis of crystal magnetization (typically c-axis) and excellent anisotropy generally have a high residual magnetic flux density Br. Accordingly, the “anisotropic magnet powder having crystal magnetic anisotropy” is a magnet powder having a residual magnetic flux density Br of 1.0 T or more. A method for measuring the residual magnetic flux density Br will be described later.

実施形態の希土類磁石の製造方法は、水素化合金（上述の水素不均化状態の組織を有する合金に等しい）が有する形状の自由度が高いという特性、即ち塑性加工性に優れるという点を利用することで、成形時、塑性加工性に劣る異方性磁石粉末の粒子同士を変形した水素化粉末によって強固に結合することができる。また、実施形態の希土類磁石の製造方法は、異方性磁石粉末の粒子同士が水素化粉末によって結合された粉末成形体に脱水素処理を施すことで、結合材である水素化粉末を最終的に磁石相に変化させられ、実質的に磁石相のみで構成される磁石素材を製造できる。実施形態の希土類磁石の製造方法は、このような磁石素材に着磁することで、従来の樹脂ボンド磁石に比較して磁石相の含有割合が高い希土類磁石を製造することができる。即ち、実施形態の希土類磁石の製造方法は、磁石相の含有割合が高いことで磁気特性に優れる希土類磁石を製造することができる。   The method for producing a rare earth magnet according to the embodiment utilizes the characteristic that the degree of freedom of the shape of the hydrogenated alloy (equivalent to the above-described alloy having the structure of the hydrogen disproportionation state) is high, that is, the excellent plastic workability. By doing so, the particles of anisotropic magnet powder inferior in plastic workability can be firmly bonded by deformed hydrogenated powder during molding. In addition, the method for producing a rare earth magnet according to the embodiment is such that the hydrogenated powder as a binder is finally obtained by performing a dehydrogenation process on a powder molded body in which particles of anisotropic magnet powder are bonded together by a hydrogenated powder. It is possible to produce a magnet material that is substantially composed only of a magnet phase. The manufacturing method of the rare earth magnet according to the embodiment can manufacture a rare earth magnet having a higher magnetic phase content than conventional resin bonded magnets by magnetizing such a magnet material. That is, the method for producing a rare earth magnet of the embodiment can produce a rare earth magnet having excellent magnetic properties due to a high content ratio of the magnet phase.

また、実施形態の希土類磁石の製造方法は、従来の樹脂ボンド磁石の製造過程と同様な工程、つまり原料粉末の準備、磁場成形、熱処理という工程を経ることで、上述のような磁気特性に優れる希土類磁石を製造できる。更に、実施形態の希土類磁石の製造方法は、成形過程で磁場を印加することで配向性を高められることから、例えば脱水素処理時に強磁場を印加するという操作を行わなくても、配向性に優れる希土類磁石（異方性磁石）を製造することができる。ここで、上記操作は、高温かつ強磁場という操作であることから、製造条件の制御が煩雑であり、大型な設備も必要になる。これに対し、実施形態の希土類磁石の製造方法は、従来の樹脂ボンド磁石の製造過程と重複する点、上述のような煩雑な制御などが必要な操作を行わなくてもよい点から、磁気特性に優れる希土類磁石を生産性よく製造できるといえる。   In addition, the method for producing a rare earth magnet according to the embodiment is excellent in magnetic characteristics as described above by going through the same steps as the production process of the conventional resin bonded magnet, that is, the steps of raw material powder preparation, magnetic field forming, and heat treatment. Rare earth magnets can be manufactured. Further, the rare earth magnet manufacturing method of the embodiment can improve the orientation by applying a magnetic field during the molding process, so that the orientation can be improved without performing an operation of applying a strong magnetic field during dehydrogenation, for example. An excellent rare earth magnet (anisotropic magnet) can be produced. Here, since the said operation is operation of high temperature and a strong magnetic field, control of manufacturing conditions is complicated and a large sized installation is also needed. On the other hand, the rare earth magnet manufacturing method of the embodiment overlaps with the conventional resin bond magnet manufacturing process, and it is not necessary to perform the operations that require complicated control as described above. It can be said that a rare earth magnet having excellent resistance can be produced with high productivity.

実施形態の希土類磁石の製造方法によって製造された希土類磁石は、異方性磁石粉末と、脱水素処理を経て最終的に希土類−鉄系合金となった領域とで実質的に構成され、上記領域が、異方性磁石粉末の粒子を結合する結合領域として機能する。即ち、この希土類磁石は、結合領域も磁石相によって構成されており、異方性磁石粉末と、脱水素処理を経た希土類−鉄系合金という磁石相のみによって実質的に構成される。そのため、この希土類磁石は、異方性磁石粉末が有する結晶磁気異方性を実質的に維持しながら、結合材を構成する希土類−鉄系合金の磁気特性をも合せ持つことができる。従って、この希土類磁石は、高い配向性を有しており（後述する配向度が高く）、磁気特性（特に、最大エネルギー積（ＢＨ）ｍａｘ、残留磁束密度Ｂｒ）に優れる。   The rare earth magnet manufactured by the method of manufacturing a rare earth magnet according to the embodiment is substantially composed of anisotropic magnet powder and a region that finally becomes a rare earth-iron alloy through dehydrogenation treatment, and the region described above. However, it functions as a bonding region for bonding particles of anisotropic magnet powder. That is, in this rare earth magnet, the bonding region is also constituted by the magnet phase, and is substantially constituted only by the anisotropic magnet powder and the magnet phase of the rare earth-iron alloy that has undergone the dehydrogenation treatment. Therefore, this rare earth magnet can have the magnetic characteristics of the rare earth-iron alloy constituting the binder while substantially maintaining the magnetocrystalline anisotropy of the anisotropic magnet powder. Therefore, this rare earth magnet has high orientation (high degree of orientation described later) and is excellent in magnetic characteristics (particularly, maximum energy product (BH) max, residual magnetic flux density Br).

（２） 実施形態に係る希土類磁石の製造方法の一例として、上記希土類元素がＮｄであり、上記再結合合金は、Ｎｄを含む希土類−鉄系合金である形態が挙げられる。   (2) As an example of the method for producing a rare earth magnet according to the embodiment, the rare earth element is Nd, and the recombination alloy is a rare earth-iron alloy containing Nd.

上記形態は、代表的には、水素化粉末としてＮｄの水素化合物を含むもの、異方性磁石粉末としてＮｄ−Ｆｅ−Ｂ系合金などのＮｄを含む組成からなるものを用意することで、Ｎｄ−Ｆｅ−Ｂ系などのＮｄ系希土類磁石を製造することができる。異方性磁石粉末が上記Ｎｄを含む組成から構成されている場合、脱水素処理時の加熱によって結晶の成長や熱分解などが生じ難く、異方性磁石粉末が有する結晶磁気異方性を維持し易い。従って、上記形態は、磁気特性に優れる希土類磁石を安定して製造することができる。   Typically, the above-mentioned form is prepared by preparing a material containing a hydrogen compound of Nd as a hydrogenated powder and a material comprising a composition containing Nd such as an Nd-Fe-B alloy as an anisotropic magnet powder. An Nd-based rare earth magnet such as a -Fe-B system can be manufactured. When the anisotropic magnet powder is composed of the composition containing Nd, the crystal magnetic anisotropy of the anisotropic magnet powder is maintained because the crystal growth or thermal decomposition is hardly caused by heating during the dehydrogenation process. Easy to do. Therefore, the said form can manufacture stably the rare earth magnet excellent in a magnetic characteristic.

（３） 実施形態に係る希土類磁石の製造方法の一例として、上記混合粉末における上記異方性磁石粉末の質量割合が５０％超９５％以下である形態が挙げられる。   (3) As an example of the method for producing a rare earth magnet according to the embodiment, a form in which the mass ratio of the anisotropic magnet powder in the mixed powder is more than 50% and not more than 95%.

上記形態は、異方性磁石粉末を過半数含むことで、異方性磁石粉末が有する結晶磁気異方性によって、磁気特性に優れる希土類磁石を製造することができる。また、上記形態は、塑性加工性に優れる水素化粉末を特定の範囲で含むことで、異方性磁石粉末の粒子同士を強固に結合できる上に、この結合材による磁気特性の向上効果も得られるため、磁気特性に優れる上に強固な希土類磁石を製造することができる。   The said form can manufacture the rare earth magnet which is excellent in a magnetic characteristic by the magnetocrystalline anisotropy which anisotropic magnet powder has by containing a majority of anisotropic magnet powder. In addition, the above-mentioned form includes the hydrogenated powder excellent in plastic workability in a specific range, so that the particles of the anisotropic magnet powder can be firmly bonded to each other, and the effect of improving the magnetic properties by the binder is also obtained. Therefore, it is possible to produce a strong rare earth magnet with excellent magnetic characteristics.

（４） 実施形態に係る希土類磁石の製造方法の一例として、上記水素化粉末の平均粒径が３μｍ以上５００μｍ以下である形態が挙げられる。   (4) As an example of the method for producing a rare earth magnet according to the embodiment, a mode in which the average particle diameter of the hydrogenated powder is 3 μm or more and 500 μm or less can be given.

上記形態は、水素化粉末の大きさが上述の特定の範囲であることで、成形時の圧力を過大にすることなく水素化粉末を十分に塑性変形させられて、異方性磁石粉末の粒子同士の結合を良好に行える。その結果、上記形態は、磁気特性に優れる上に強固な希土類磁石を生産性よく製造することができる。   In the above form, the size of the hydrogenated powder is in the specific range described above, so that the hydrogenated powder can be sufficiently plastically deformed without excessive pressure during molding. Bonding can be performed well. As a result, the above-described embodiment can produce a strong rare earth magnet with high productivity as well as excellent magnetic characteristics.

（５） 実施形態に係る希土類磁石の製造方法の一例として、上記異方性磁石粉末が、希土類元素と、鉄族元素と、Ｂ及び炭素（Ｃ）から選択される少なくとも１種の元素とを含む希土類−鉄系合金からなり、この希土類−鉄系合金の平均結晶粒径が７００ｎｍ以下である形態が挙げられる。   (5) As an example of the method for producing a rare earth magnet according to the embodiment, the anisotropic magnet powder includes a rare earth element, an iron group element, and at least one element selected from B and carbon (C). The rare earth-iron-based alloy is included, and the rare earth-iron-based alloy has an average crystal grain size of 700 nm or less.

上記異方性磁石粉末として、例えば、Ｎｄ−Ｆｅ−Ｂ系合金、Ｎｄ−Ｆｅ−Ｃ系合金からなるものが挙げられる。上記形態は、異方性磁石粉末を構成するこれらの合金の平均結晶粒径が上述の特定の範囲を満たす非常に微細な多結晶体で構成されていることで微細結晶に起因する保磁力の向上効果が期待できる。従って、上記形態は、磁気特性（特に残留磁束密度、保磁力）により優れる希土類磁石を製造することができる。   As said anisotropic magnet powder, what consists of a Nd-Fe-B type alloy and a Nd-Fe-C type alloy is mentioned, for example. In the above-mentioned form, the average crystal grain size of these alloys constituting the anisotropic magnet powder is composed of a very fine polycrystal satisfying the above-mentioned specific range, so that the coercive force due to the fine crystals is reduced. An improvement effect can be expected. Therefore, the said form can manufacture the rare earth magnet which is excellent in a magnetic characteristic (especially residual magnetic flux density, coercive force).

（６） 実施形態に係る希土類磁石の製造方法の一例として、上記異方性磁石粉末の平均粒径が３μｍ以上５００μｍ以下である形態が挙げられる。   (6) As an example of the method for producing a rare earth magnet according to the embodiment, a form in which the average particle diameter of the anisotropic magnet powder is 3 μm or more and 500 μm or less can be given.

上記形態は、異方性磁石粉末の平均粒径が上述の特定の範囲であることで、成形時、異方性磁石粉末の粒子の割れなどを防止し易く、かつ各粒子のそれぞれが、変形した水素化粉末の粒子と良好に接触することができる。その結果、上記形態は、異方性磁石粉末の粒子同士の結合を良好に行えて、磁気特性に優れる上に強固な希土類磁石を生産性よく製造することができる。   In the above-mentioned form, the average particle diameter of the anisotropic magnet powder is in the specific range described above, so that it is easy to prevent cracking of the particles of the anisotropic magnet powder during molding, and each particle is deformed. It is possible to make good contact with the particles of the hydrogenated powder. As a result, the above-mentioned form can satisfactorily bond the particles of anisotropic magnet powder, and can produce a strong rare earth magnet with high productivity and excellent magnetic properties.

（７） 実施形態に係る希土類磁石の製造方法の一例として、上記粉末成形体の相対密度が７０％以上である形態が挙げられる。   (7) As an example of the method for producing a rare earth magnet according to the embodiment, there is a form in which the relative density of the powder compact is 70% or more.

粉末成形体の相対密度が上述の特定の範囲を満たす場合、この粉末成形体は、水素化粉末と異方性磁石粉末との合計の含有割合が高いといえる。このような高密度の粉末成形体を用いて磁石素材を製造することで、得られた磁石素材も、粉末成形体の相対密度を実質的に維持して、高い相対密度を有することができ、高密度な磁石を製造することができる。従って、上記形態は、磁石相の含有割合が高く、磁気特性に優れる希土類磁石を製造することができる。   When the relative density of the powder compact satisfies the specific range described above, it can be said that the powder compact has a high total content of the hydrogenated powder and the anisotropic magnet powder. By producing a magnet material using such a high-density powder molded body, the obtained magnet material can also substantially maintain the relative density of the powder molded body and have a high relative density, A high-density magnet can be manufactured. Therefore, the said form can manufacture the rare earth magnet which is high in the content rate of a magnet phase, and is excellent in a magnetic characteristic.

［本発明の実施形態の詳細］
以下、図面を参照して、実施形態に係る希土類磁石の製造方法、及びこの製造方法によって製造される希土類磁石を説明する。図１，図２において、六角形は結晶を模式的に示し、六角形内の矢印は結晶の配向方向を示す。六角形内の矢印の方向は例示である。結晶は、説明の便宜上、拡大して示す。また、図２は、図１に示す希土類磁石１（磁石素材１０）について、破線円で囲まれる部分の組織を拡大して示す。まず、希土類磁石を説明する。 [Details of the embodiment of the present invention]
Hereinafter, with reference to drawings, the manufacturing method of the rare earth magnet concerning an embodiment, and the rare earth magnet manufactured by this manufacturing method are explained. 1 and 2, hexagons schematically indicate crystals, and arrows within the hexagons indicate crystal orientation directions. The direction of the arrow in the hexagon is exemplary. The crystals are shown enlarged for convenience of explanation. FIG. 2 is an enlarged view of the structure of the portion surrounded by a broken-line circle in the rare earth magnet 1 (magnet material 10) shown in FIG. First, a rare earth magnet will be described.

（希土類磁石）
図１，図２に示す希土類磁石１は、磁石相を主体とし、残部が主として気孔である磁石であり、結晶磁化容易軸の配向度（以下、結晶配向度と呼ぶことがある）が異なる複数の磁石相を備える。具体的には、希土類磁石１は、結晶磁気異方性を有する磁石相（異方性領域１２）と、異方性領域１２の結晶配向度よりも低い結晶配向度を有する磁石相とを備える。この結晶配向度が低い磁石相は、異方性領域１２間に介在されて結合材として機能する磁性結合領域１３である。このように希土類磁石１は、異方性領域１２間に介在される結合材をも磁石相によって構成されていることから、磁石相の含有割合（ここでは異方性領域１２と磁性結合領域１３との合計の含有割合）が従来の樹脂ボンド磁石よりも高い。特に、結合材を構成する磁石相も高い磁力（残留磁束密度や最大エネルギー積）を有する希土類磁石であることから、希土類磁石１は、従来の樹脂ボンド磁石よりも、磁力向上の幅が大きく、磁気特性に優れる。希土類磁石１は、磁性結合領域１３を有する点で従来の樹脂ボンド磁石や焼結磁石と異なり、異方性領域１２を有する点で特許文献２に記載される圧粉磁石と異なる。以下、各領域を順に説明する。 (Rare earth magnet)
A rare earth magnet 1 shown in FIG. 1 and FIG. 2 is a magnet mainly composed of a magnet phase, the remainder being mainly pores, and a plurality of different degrees of orientation of the easy axis of crystal magnetization (hereinafter sometimes referred to as crystal orientation). The magnet phase is provided. Specifically, the rare earth magnet 1 includes a magnet phase (anisotropic region 12) having crystal magnetic anisotropy and a magnet phase having a crystal orientation degree lower than the crystal orientation degree of the anisotropic region 12. . The magnet phase having a low degree of crystal orientation is a magnetic coupling region 13 that is interposed between the anisotropic regions 12 and functions as a binder. Thus, since the rare earth magnet 1 is also composed of the magnetic phase as a binder interposed between the anisotropic regions 12, the content ratio of the magnet phase (here, the anisotropic region 12 and the magnetic coupling region 13). And the total content ratio) is higher than that of conventional resin bonded magnets. In particular, since the magnet phase constituting the binder is a rare earth magnet having a high magnetic force (residual magnetic flux density and maximum energy product), the rare earth magnet 1 has a larger range of magnetic force improvement than the conventional resin bonded magnet, Excellent magnetic properties. The rare earth magnet 1 is different from conventional resin bonded magnets and sintered magnets in that it has a magnetic coupling region 13, and is different from the dust magnet described in Patent Document 2 in that it has an anisotropic region 12. Hereinafter, each region will be described in order.

・異方性領域
・・機能
異方性領域１２は、それ自体の結晶磁気異方性を活かして、高い結晶配向度を有することから、主として、高い磁気特性を有する磁石領域として機能する。 -Anisotropic region-Function The anisotropic region 12 functions mainly as a magnet region having high magnetic properties because it has a high degree of crystal orientation by utilizing its own magnetocrystalline anisotropy.

・・組成
異方性領域１２を構成する希土類磁石相の組成は、代表的には、希土類元素と鉄族元素とを含む希土類−鉄系合金が挙げられる。希土類元素は、スカンジウム（Ｓｃ）、イットリウム（Ｙ）、ランタノイド、及びアクチノイドから選択される１種以上の元素が挙げられる。特に、希土類元素として、Ｎｄ、サマリウム（Ｓｍ）、プラセオジム（Ｐｒ）、セリウム（Ｃｅ）、ジスプロシウム（Ｄｙ）、及びＹから選択される少なくとも１種の元素を含むと、磁気特性に優れて好ましい。とりわけ、Ｎｄ−Ｆｅ−Ｂ系合金、Ｎｄ−Ｆｅ−Ｃ系合金などのＮｄを含む組成では、後述するように成形後に脱水素処理を行っても、粒成長を抑制でき、高い磁気特性を有することができて好ましい。 .. Composition The composition of the rare earth magnet phase constituting the anisotropic region 12 is typically a rare earth-iron alloy containing a rare earth element and an iron group element. Examples of the rare earth element include one or more elements selected from scandium (Sc), yttrium (Y), lanthanoids, and actinoids. In particular, it is preferable that the rare earth element includes at least one element selected from Nd, samarium (Sm), praseodymium (Pr), cerium (Ce), dysprosium (Dy), and Y because of excellent magnetic properties. In particular, compositions containing Nd such as Nd—Fe—B alloys and Nd—Fe—C alloys can suppress grain growth and have high magnetic properties even when dehydrogenation is performed after molding as will be described later. This is preferable.

Ｎｄを含む組成では、Ｎｄの含有量が２８質量％以上３５質量％以下であることが好ましい。Ｎｄの含有量が、Ｎｄ２Ｆｅ１４Ｂなどの化学量論比である２８質量％以上である場合、結晶粒界にＮｄのリッチ相が均一的に分散した結晶組織とすることができる。このような結晶組織は、結晶粒が希土類元素のリッチ相によって磁気的に孤立された組織といえ、磁気特性に優れて好ましい。 In the composition containing Nd, the Nd content is preferably 28% by mass or more and 35% by mass or less. When the Nd content is 28% by mass or more which is a stoichiometric ratio of Nd 2 Fe 14 B or the like, a crystal structure in which the rich phase of Nd is uniformly dispersed in the crystal grain boundaries can be obtained. Such a crystal structure can be said to be a structure in which crystal grains are magnetically isolated by a rich phase of a rare earth element, and is excellent in magnetic characteristics.

鉄族元素は、Ｆｅ、コバルト（Ｃｏ）、及びニッケル（Ｎｉ）から選択される１種以上の元素が挙げられる。代表的には、Ｆｅを希土類−鉄系合金の主体（５０質量％超）とする形態が挙げられる。その他、例えば、ＦｅとＣｏとの双方を含む形態が挙げられる。   Examples of the iron group element include one or more elements selected from Fe, cobalt (Co), and nickel (Ni). A typical example is an embodiment in which Fe is a main component (greater than 50% by mass) of a rare earth-iron alloy. In addition, the form containing both Fe and Co is mentioned, for example.

上記希土類−鉄系合金は、希土類元素及び鉄族元素以外の元素として、代表的には、Ｂ及びＣから選択される１種以上の元素を含む。ＢやＣの含有量は、０．１質量％以上５．０質量％以下、更に０．５質量％以上１．５質量％以下が挙げられる。   The rare earth-iron-based alloy typically contains one or more elements selected from B and C as elements other than rare earth elements and iron group elements. Examples of the content of B and C include 0.1% by mass or more and 5.0% by mass or less, and further 0.5% by mass or more and 1.5% by mass or less.

上記希土類−鉄系合金におけるその他の添加元素として、ガリウム（Ｇａ）、銅（Ｃｕ）、アルミニウム（Ａｌ）、珪素（Ｓｉ）、チタン（Ｔｉ）、マンガン（Ｍｎ）及びニオブ（Ｎｂ）から選択される１種以上の元素が挙げられる。これらの添加元素の含有量（複数の場合には合計含有量）は、０．１質量％以上２０質量％以下、更に０．１質量％以上５質量％以下が挙げられる。これらの元素を含有することで、例えば、保磁力の向上などの効果が望める。   Other additive elements in the rare earth-iron alloy are selected from gallium (Ga), copper (Cu), aluminum (Al), silicon (Si), titanium (Ti), manganese (Mn) and niobium (Nb). One or more elements. The content of these additive elements (the total content in the case of plural elements) is 0.1% by mass or more and 20% by mass or less, and further 0.1% by mass or more and 5% by mass or less. By containing these elements, for example, an effect such as improvement in coercive force can be expected.

具体的な希土類−鉄系合金の組成としては、Ｎｄ−Ｆｅ−Ｂ合金（例えば、Ｎｄ２Ｆｅ１４Ｂ）、Ｎｄ−Ｆｅ−Ｃｏ−Ｂ合金、Ｎｄ−Ｆｅ−Ｃ合金、Ｎｄ−Ｆｅ−Ｃｏ−Ｃ合金などが挙げられる。 Specific compositions of rare earth-iron alloys include Nd—Fe—B alloys (for example, Nd 2 Fe 14 B), Nd—Fe—Co—B alloys, Nd—Fe—C alloys, Nd—Fe—Co. -C alloy etc. are mentioned.

希土類磁石１の一例として、全ての異方性領域１２が実質的に等しい組成で構成される形態、即ち、全ての異方性領域１２が単一組成で構成される形態が挙げられる。この単一の磁石相からなる異方性領域１２を有する形態は、原料に、所望の材質の希土類−鉄系合金からなる異方性磁石粉末を一つ用意することで得られる。別の例として、異方性領域１２が複数の異なる組成で構成される形態とすることができる。この複数の異なる磁石相からなる異方性領域１２を有する形態は、原料に、所望の材質の希土類−鉄系合金からなる異方性磁石粉末を複数用意することで得られる。   As an example of the rare earth magnet 1, a form in which all the anisotropic regions 12 are configured with substantially the same composition, that is, a mode in which all the anisotropic regions 12 are configured with a single composition can be cited. The form having the anisotropic region 12 composed of a single magnet phase can be obtained by preparing one anisotropic magnet powder composed of a rare earth-iron alloy of a desired material as a raw material. As another example, the anisotropic region 12 may be formed of a plurality of different compositions. The form having the anisotropic regions 12 made of a plurality of different magnet phases can be obtained by preparing a plurality of anisotropic magnet powders made of a rare earth-iron alloy of a desired material as a raw material.

・・結晶磁気異方性（結晶配向度）
希土類磁石１の表面又は断面（以下、観察面と呼ぶことがある）について、結晶磁化容易軸の配向度（結晶配向度）を調べ、結晶配向度が７０％以上である領域を、結晶磁気異方性を有する領域として抽出したとき、抽出した各領域をそれぞれ異方性領域１２と呼ぶ。各異方性領域１２は、結晶配向度が高いほど磁気異方性に優れ、磁気特性に優れる希土類磁石１となる。従って、各異方性領域１２の結晶配向度はそれぞれ、７５％以上、８０％以上、８５％以上、更に８７％以上、更には９０％以上であることが好ましい。また、各異方性領域１２の結晶配向度は異なっていてもよいが、できるだけ高くかつ結晶配向度のばらつきが小さい、好ましくは結晶配向度が実質的に同じであると、磁気特性により優れる希土類磁石１となって好ましい。 ..Crystal magnetic anisotropy (crystal orientation)
With respect to the surface or cross section of the rare earth magnet 1 (hereinafter sometimes referred to as an observation surface), the orientation degree (crystal orientation degree) of the easy axis of crystal magnetization is examined, and a region where the crystal orientation degree is 70% or more is determined. When extracted as a region having directionality, each extracted region is referred to as an anisotropic region 12. Each anisotropic region 12 becomes a rare earth magnet 1 having a higher degree of crystal orientation and better magnetic anisotropy and better magnetic properties. Therefore, the degree of crystal orientation of each anisotropic region 12 is preferably 75% or more, 80% or more, 85% or more, further 87% or more, and more preferably 90% or more. Further, the degree of crystal orientation of each anisotropic region 12 may be different, but rare earths that are excellent in magnetic properties when they are as high as possible and the variation in crystal orientation is small, preferably the crystal orientation is substantially the same. The magnet 1 is preferable.

異方性領域１２の抽出には、例えば、希土類磁石１の観察面について走査型電子顕微鏡（ＳＥＭ）観察を行い、観察像を観察面に平行な方向で評価した電子線後方散乱回折法（ＥＢＳＰ。ＥＢＳＤと呼ばれることがある）による方位マップを利用することが挙げられる。結晶の方位を色別で表わすカラーマップを利用することで、例えば、特定の色が集まった領域を異方性領域１２として抽出することができる。なお、各異方性領域１２はそれぞれ、原料に用いた異方性磁石粉末の粒子によって形成されることから、理想的には、各異方性領域１２と上記異方性磁石粉末の粒子がつくる領域とは等しくなる。しかし、カラーマップでは、異方性領域１２と上記異方性磁石粉末の粒子がつくる領域とが完全に一致せず、異方性領域１２の抽出にあたり、誤差を含み得る。その結果、後述する平均粒径や結晶粒径、存在割合などに誤差を含むことがある。このような誤差を含むことを許容する。異方性領域１２の結晶配向度は、例えば、希土類磁石１の観察面から抽出した異方性領域１２をＸ線回折して、最大ピーク強度Ｉｍａｘと、結晶磁化容易軸（代表的にはｃ軸）のピーク強度Ｉｃとを調べ、ピーク強度比（Ｉｃ／Ｉｍａｘ）×１００を算出して求めることが挙げられる。３個以上の観察面をとり、各観察面について３個以上の異方性領域１２の結晶配向度を上述のようにして求め、合計９個以上の結晶配向度の平均を異方性領域１２の結晶配向度とする。   The extraction of the anisotropic region 12 is performed by, for example, scanning electron microscope (SEM) observation of the observation surface of the rare earth magnet 1 and evaluating the observation image in a direction parallel to the observation surface (EBSP). (Sometimes referred to as EBSD). By using a color map that represents crystal orientations by color, for example, a region where specific colors are collected can be extracted as the anisotropic region 12. Since each anisotropic region 12 is formed by particles of anisotropic magnet powder used as a raw material, ideally each anisotropic region 12 and the particles of anisotropic magnet powder are It is equal to the area to be created. However, in the color map, the anisotropic region 12 and the region formed by the particles of the anisotropic magnet powder do not completely match, and an error may be included in extracting the anisotropic region 12. As a result, an error may be included in an average particle diameter, a crystal particle diameter, an abundance ratio, and the like described later. It is allowed to include such an error. The degree of crystal orientation of the anisotropic region 12 is determined by, for example, subjecting the anisotropic region 12 extracted from the observation surface of the rare earth magnet 1 to X-ray diffraction, the maximum peak intensity Imax, the crystal magnetization easy axis (typically c And the peak intensity ratio (Ic / Imax) × 100 is calculated. Taking three or more observation planes, the crystal orientation degree of three or more anisotropic regions 12 for each observation plane is determined as described above, and the average of the total nine or more crystal orientation degrees is calculated as anisotropic region 12. The degree of crystal orientation.

・・組織
異方性領域１２を構成する希土類磁石相は、代表的には図２に示すように非常に微細な多結晶体で構成される。希土類磁石１の一例として、異方性領域１２を構成する希土類−鉄系合金の平均結晶粒径が７００ｎｍ以下である形態が挙げられる。平均結晶粒径が７００ｎｍ以下と微細であることで、微細結晶組織に起因する磁気特性（特に保磁力）の向上効果が期待できる。上記平均結晶粒径は、小さいほど単磁区粒子臨界径に近くなり磁気特性に優れることから、５００ｎｍ以下、更に３００ｎｍ以下が好ましい。異方性領域１２を構成する希土類−鉄系合金の結晶粒径は、原料に用いる異方性磁石粉末を構成する希土類−鉄系合金の結晶粒径及び製造過程の熱処理条件の影響を受ける。熱処理温度（特に脱水素処理時の温度）が高過ぎると、結晶が成長して粗大になる傾向にある。従って、原料の結晶の大きさや熱処理条件を調整することで、希土類磁石１に備える異方性領域１２の平均結晶粒径を所望の値にすることができる。 .. Structure The rare earth magnet phase constituting the anisotropic region 12 is typically composed of a very fine polycrystal as shown in FIG. As an example of the rare earth magnet 1, a form in which the average crystal grain size of the rare earth-iron alloy constituting the anisotropic region 12 is 700 nm or less can be given. When the average crystal grain size is as fine as 700 nm or less, an effect of improving magnetic properties (particularly coercive force) due to the fine crystal structure can be expected. The smaller the average crystal grain size, the closer to the single domain particle critical diameter and the better the magnetic properties. Therefore, the average crystal grain size is preferably 500 nm or less, and more preferably 300 nm or less. The crystal grain size of the rare earth-iron alloy constituting the anisotropic region 12 is affected by the crystal grain size of the rare earth-iron alloy constituting the anisotropic magnet powder used as a raw material and the heat treatment conditions in the manufacturing process. If the heat treatment temperature (particularly the temperature during dehydrogenation) is too high, crystals tend to grow and become coarse. Therefore, the average crystal grain size of the anisotropic region 12 provided in the rare earth magnet 1 can be set to a desired value by adjusting the crystal size of the raw material and the heat treatment conditions.

異方性領域１２の平均結晶粒径は、以下のように測定する。希土類磁石１の表面又は断面（観察面）についてＳＥＭ−ＥＢＳＰなどを利用して、上述のように異方性領域１２を抽出し、抽出した異方性領域１２内の各結晶粒の面積をそれぞれ調べ、各面積の円相当径を結晶粒径とする。３個以上の観察面をとり、各観察面について１０個以上の結晶粒径を求め、合計３０個以上の結晶粒径の平均を平均結晶粒径とする。この平均結晶粒径や後述する異方性領域１２の平均粒径、その他後述する種々のパラメータを、顕微鏡観察像を用いて算出する場合には、市販の画像処理ソフトを用いると容易に算出できる。   The average crystal grain size of the anisotropic region 12 is measured as follows. Using the SEM-EBSP or the like for the surface or cross section (observation surface) of the rare earth magnet 1, the anisotropic region 12 is extracted as described above, and the area of each crystal grain in the extracted anisotropic region 12 is respectively determined. The circle equivalent diameter of each area is taken as the crystal grain size. Three or more observation planes are taken, 10 or more crystal grain sizes are obtained for each observation plane, and the average of the total 30 or more crystal grain sizes is defined as the average crystal grain size. When calculating the average crystal grain size, the average grain size of the anisotropic region 12 described later, and other various parameters described later using a microscope observation image, it can be easily calculated using commercially available image processing software. .

・・形状及び大きさ
希土類磁石１は、複数の異方性領域１２を備える。ここで、各異方性領域１２は、原料の組成、大きさだけでなく、形状も実質的に維持する。従って、原料に、所望の組成・大きさ・形状の異方性磁石粉末を用いることで、各異方性領域１２の組成・大きさ・形状を所望のものにすることができる。例えば、異方性領域１２の平均粒径は３μｍ以上５００μｍ以下が挙げられる。異方性領域１２の平均粒径が上述の範囲を満たす場合、原料に、平均粒径が上述の範囲を満たす異方性磁石粉末を用いたといえる。原料に上記範囲を満たす異方性磁石粉末を用いることで、異方性磁石粉末の粒子同士を結合材によって良好に結合することができる。そのため、この希土類磁石１は、異方性領域１２同士が磁性結合領域１３によって強固に結合された強固な磁石とすることができる。異方性領域１２の平均粒径は、３０μｍ以上４００μｍ以下、更に５０μｍ以上３００μｍ以下とすることができる。 -Shape and size The rare-earth magnet 1 includes a plurality of anisotropic regions 12. Here, each anisotropic region 12 substantially maintains not only the composition and size of the raw material but also the shape. Therefore, the composition, size, and shape of each anisotropic region 12 can be made desired by using anisotropic magnet powder having a desired composition, size, and shape as a raw material. For example, the average particle diameter of the anisotropic region 12 is 3 μm or more and 500 μm or less. In the case where the average particle size of the anisotropic region 12 satisfies the above range, it can be said that anisotropic magnet powder having the average particle size satisfying the above range was used as the raw material. By using the anisotropic magnet powder satisfying the above range as the raw material, the particles of the anisotropic magnet powder can be satisfactorily bonded by the binder. Therefore, the rare earth magnet 1 can be a strong magnet in which the anisotropic regions 12 are firmly coupled by the magnetic coupling region 13. The average particle diameter of the anisotropic region 12 can be 30 μm or more and 400 μm or less, and further 50 μm or more and 300 μm or less.

異方性領域１２の平均粒径は、以下のように測定する。希土類磁石１の表面又は断面（観察面）についてＳＥＭ−ＥＢＳＰなどを利用して、上述のように異方性領域１２を抽出し、観察面に存在する各異方性領域１２の面積をそれぞれ調べ、各面積の円相当径を異方性領域１２の直径とする。３個以上の観察面をとり、各観察面について１０個以上の異方性領域１２の直径を求め、合計３０個以上の直径の平均を異方性領域１２の平均粒径とする。   The average particle diameter of the anisotropic region 12 is measured as follows. Using SEM-EBSP or the like for the surface or cross section (observation surface) of the rare earth magnet 1, the anisotropic region 12 is extracted as described above, and the area of each anisotropic region 12 existing on the observation surface is examined. The equivalent circle diameter of each area is defined as the diameter of the anisotropic region 12. Taking three or more observation surfaces, the diameter of 10 or more anisotropic regions 12 is obtained for each observation surface, and the average of the total of 30 or more diameters is defined as the average particle diameter of the anisotropic regions 12.

・・含有量
希土類磁石１における異方性領域１２の存在割合が高いほど、結晶磁気異方性を有する領域が相対的に多くなり、配向性が高められて、磁気特性に優れる希土類磁石１となる。従って、異方性領域１２の存在割合は、過半数、具体的には体積割合で５０％超が好ましく、６０％以上、更に７０％以上、更には７５％以上がより好ましい。異方性領域１２の存在割合は、原料に用いる異方性磁石粉末の配合割合に依存し、この配合割合を実質的に維持する。従って、所望の配合割合を有する混合粉末（後述）を原料に用いることで、希土類磁石１における異方性領域１２の存在割合（換言すれば、後述する磁性結合領域１３の存在割合）を所望の値にすることができる。 .. Content The higher the proportion of the anisotropic region 12 in the rare earth magnet 1, the more the region having the magnetocrystalline anisotropy becomes, the orientation is enhanced, and the rare earth magnet 1 having excellent magnetic properties Become. Therefore, the abundance ratio of the anisotropic region 12 is preferably a majority, specifically, more than 50% by volume, more preferably 60% or more, further 70% or more, and even more preferably 75% or more. The abundance ratio of the anisotropic region 12 depends on the blending ratio of the anisotropic magnet powder used as the raw material and substantially maintains this blending ratio. Therefore, by using a mixed powder having a desired blending ratio (described later) as a raw material, the abundance ratio of the anisotropic region 12 in the rare earth magnet 1 (in other words, the abundance ratio of the magnetic coupling region 13 described later) is desired. Can be a value.

上記異方性領域１２の存在割合は、以下のように測定する。上述のようにＳＥＭ−ＥＢＳＰなどを利用して異方性領域１２を抽出し、観察面における異方性領域１２が占める面積割合を求める。簡易的には、この面積割合を異方性領域１２の存在割合（体積割合）とすることができる。   The abundance ratio of the anisotropic region 12 is measured as follows. As described above, the anisotropic region 12 is extracted using SEM-EBSP or the like, and the area ratio occupied by the anisotropic region 12 on the observation surface is obtained. In simple terms, this area ratio can be set as the existence ratio (volume ratio) of the anisotropic region 12.

・磁性結合領域
・・機能
磁性結合領域１３は、希土類磁石１内に均一的に分散して存在する複数の異方性領域１２を相互に結合する結合材として機能する。かつ、磁性結合領域１３は、異方性領域１２よりも配向性が低いものの、希土類磁石相によって構成されることから、その磁気特性を活かして、磁石領域としても機能する。希土類磁石１は、上述の異方性領域１２と磁性結合領域１３という二つの希土類磁石相から実質的に構成されることから、高い磁気特性を有する。 Magnetic coupling region Function The magnetic coupling region 13 functions as a binding material that couples a plurality of anisotropic regions 12 that are uniformly dispersed in the rare earth magnet 1. In addition, although the magnetic coupling region 13 has a lower orientation than the anisotropic region 12, the magnetic coupling region 13 is composed of a rare earth magnet phase, and thus functions as a magnet region by utilizing its magnetic characteristics. Since the rare earth magnet 1 is substantially composed of the two rare earth magnet phases of the anisotropic region 12 and the magnetic coupling region 13 described above, it has high magnetic properties.

・・組成
磁性結合領域１３を構成する希土類磁石相の組成は、上述の異方性領域１２と同様に、代表的には、希土類元素と鉄族元素とを含む希土類−鉄系合金が挙げられる。希土類−鉄系合金の詳細については、上述の異方性領域１２の「組成」の項と同様である。特に、Ｎｄ−Ｆｅ−Ｂ系合金などのＮｄを含む組成では、後述するように成形後に脱水素処理を行うことで磁石相（Ｎｄ−Ｆｅ−Ｂ系合金などの再結合合金）を容易に形成できることから、成形後の熱処理工程が少ない上に、異方性領域１２の粒成長を抑制し易い。そのため、Ｎｄを含む組成では、高い磁気特性を有する希土類磁石１とすることができて好ましい。Ｓｍを含む組成では、熱安定性に優れる上に、Ｎｄ−Ｆｅ−Ｂ系合金よりも更に磁気特性（特に、最大エネルギー積）に優れる希土類磁石１とすることができて好ましい。 .. Composition The composition of the rare earth magnet phase constituting the magnetic coupling region 13 is typically a rare earth-iron-based alloy containing a rare earth element and an iron group element, similarly to the anisotropic region 12 described above. . The details of the rare earth-iron alloy are the same as those in the “composition” section of the anisotropic region 12 described above. In particular, in a composition containing Nd such as an Nd—Fe—B alloy, a magnet phase (recombinant alloy such as an Nd—Fe—B alloy) can be easily formed by performing a dehydrogenation process after forming as described later. Therefore, the number of heat treatment steps after molding is small, and the grain growth in the anisotropic region 12 is easily suppressed. Therefore, a composition containing Nd is preferable because the rare earth magnet 1 having high magnetic properties can be obtained. The composition containing Sm is preferable because it is excellent in thermal stability and can be made into the rare earth magnet 1 that is further excellent in magnetic properties (particularly, maximum energy product) as compared with the Nd—Fe—B alloy.

希土類磁石１では、代表的には、全ての磁性結合領域１３が実質的に等しい組成で構成される。この単一組成で構成される磁性結合領域１３を有する形態は、原料に、所望の材質の水素化合金からなる水素化粉末を一つ用意することで得られる。また、この形態は、脱水素条件を制御し易く、希土類磁石１を生産性よく製造できる。   In the rare earth magnet 1, all the magnetic coupling regions 13 are typically configured with substantially the same composition. The form having the magnetic coupling region 13 composed of this single composition can be obtained by preparing one hydrogenated powder made of a hydrogenated alloy of a desired material as a raw material. Moreover, this form is easy to control dehydrogenation conditions, and can manufacture the rare earth magnet 1 with high productivity.

希土類磁石１の一例として、上述の異方性領域１２の組成と磁性結合領域１３の組成とが実質的に全て等しい形態が挙げられる。この形態は、一様な材質の希土類−鉄系合金で構成されることから、磁石の使用環境の選択などを行い易く、利便性に優れる。また、この形態は、耐環境性の表面処理の施工も容易である。別の例として、異方性領域１２の組成が実質的に単一組成である場合に磁性結合領域１３の組成とは異なる形態、異方性領域１２の組成が複数の異なる組成で構成される場合にその一部の組成と、磁性結合領域１３の組成とが異なる形態が挙げられる。これらの形態は、各組成の磁気特性に基づく効果を期待できる。   As an example of the rare earth magnet 1, there is a form in which the composition of the anisotropic region 12 and the composition of the magnetic coupling region 13 are substantially equal. Since this form is composed of a rare earth-iron alloy of a uniform material, it is easy to select the environment in which the magnet is used, and is excellent in convenience. Moreover, this form is also easy to perform environment-resistant surface treatment. As another example, when the composition of the anisotropic region 12 is substantially a single composition, the composition is different from the composition of the magnetic coupling region 13 and the composition of the anisotropic region 12 is composed of a plurality of different compositions. In some cases, there is a form in which a part of the composition is different from the composition of the magnetic coupling region 13. These forms can be expected to have an effect based on the magnetic characteristics of each composition.

・・結晶磁気異方性（結晶配向度）
希土類磁石１の表面又は断面（観察面）について、結晶磁化容易軸の配向度（結晶配向度）を調べ、結晶配向度が７０％未満である領域、即ち、磁気異方性が相対的に低い領域を抽出したとき、抽出した各領域をそれぞれ磁性結合領域１３と呼ぶ。簡易的には、磁性結合領域１３とは、上記観察面から上述の異方性領域１２及び気孔を除いた残部の領域といえる。磁性結合領域１３の結晶配向度は、代表的には５０％程度であり、いわば等方性領域といえる。磁性結合領域１３も、結晶配向度が高いほど、磁気特性に優れる希土類磁石１となる。従って、各磁性結合領域１３の結晶配向度は、５５％以上、更に６０％以上とすることができる。磁性結合領域１３の結晶配向度は、例えば、後述するように脱水素処理時に強磁場を印加することで高めることができる。磁性結合領域１３の抽出、結晶配向度の測定は、上述の異方性領域１２の場合と同様にすることができる。希土類磁石１の断面（観察面）についてＳＥＭ−ＥＢＳＰなどを利用することで、上述のように結晶の配向状況が観察でき、配向がランダムである領域を磁性結合領域１３として抽出することができる。 ..Crystal magnetic anisotropy (crystal orientation)
The surface or cross section (observation surface) of the rare earth magnet 1 is examined for the degree of orientation of the easy axis of crystal magnetization (crystal orientation), and the region where the crystal orientation is less than 70%, that is, the magnetic anisotropy is relatively low. When the region is extracted, each extracted region is called a magnetic coupling region 13. For simplicity, the magnetic coupling region 13 can be said to be the remaining region excluding the anisotropic region 12 and pores from the observation surface. The degree of crystal orientation of the magnetic coupling region 13 is typically about 50%, which can be said to be an isotropic region. The magnetic coupling region 13 also becomes a rare-earth magnet 1 having superior magnetic characteristics as the degree of crystal orientation is higher. Therefore, the degree of crystal orientation of each magnetic coupling region 13 can be 55% or more, and further 60% or more. The degree of crystal orientation of the magnetic coupling region 13 can be increased, for example, by applying a strong magnetic field during the dehydrogenation process as will be described later. The extraction of the magnetic coupling region 13 and the measurement of the degree of crystal orientation can be performed in the same manner as in the case of the anisotropic region 12 described above. By using SEM-EBSP or the like for the cross section (observation surface) of the rare earth magnet 1, the orientation state of the crystal can be observed as described above, and a region where the orientation is random can be extracted as the magnetic coupling region 13.

・・組織
磁性結合領域１３を構成する希土類磁石相は、代表的には図２に示すように微細な多結晶体で構成される。磁性結合領域１３も、上述の異方性領域１２と同様に、微細結晶組織であると微細結晶組織に起因する磁気特性（特に保磁力）の向上効果が期待できて好ましい。例えば、磁性結合領域１３を構成する希土類−鉄系合金の平均結晶粒径は、７００ｎｍ以下、更に５００ｎｍ以下、更には３００ｎｍ以下が好ましい。磁性結合領域１３を構成する希土類−鉄系合金の結晶粒径は、代表的には、製造過程の熱処理条件の影響を受ける。熱処理温度（特に脱水素処理時の温度）が高過ぎると、結晶が成長して粗大になる傾向にある。従って、熱処理条件を調整することで、希土類磁石１に備える磁性結合領域１３の平均結晶粒径を所望の値にすることができる。磁性結合領域１３の平均結晶粒径の測定は、上述の異方性領域１２の場合と同様にすることができる。 .. Structure The rare earth magnet phase constituting the magnetic coupling region 13 is typically composed of a fine polycrystal as shown in FIG. Similarly to the anisotropic region 12 described above, the magnetic coupling region 13 is also preferably a fine crystal structure because it can be expected to improve the magnetic characteristics (particularly the coercive force) due to the fine crystal structure. For example, the average crystal grain size of the rare earth-iron alloy constituting the magnetic coupling region 13 is preferably 700 nm or less, more preferably 500 nm or less, and further preferably 300 nm or less. The crystal grain size of the rare earth-iron alloy constituting the magnetic coupling region 13 is typically affected by the heat treatment conditions in the manufacturing process. If the heat treatment temperature (particularly the temperature during dehydrogenation) is too high, crystals tend to grow and become coarse. Therefore, the average crystal grain size of the magnetic coupling region 13 provided in the rare earth magnet 1 can be set to a desired value by adjusting the heat treatment conditions. The average crystal grain size of the magnetic coupling region 13 can be measured in the same manner as in the anisotropic region 12 described above.

・・形状及び大きさ
希土類磁石１は、複数の磁性結合領域１３を備える。また、各磁性結合領域１３はそれぞれ、代表的には、製造過程（成形工程の圧縮）で塑性変形して、異方性領域１２間につくられる空間を埋めるように充填された素材によって形成される。そのため、各磁性結合領域１３は、上記空間に応じて種々の形状をとり得る。このような磁性結合領域１３の平均粒径を、上述の異方性領域１２の「形状」の項で述べた平均粒径の測定方法と同様にして求めた場合、平均粒径は３μｍ以上５００μｍ以下が挙げられる。磁性結合領域１３の平均粒径が上述の範囲を満たす場合、原料に、平均粒径が上記範囲を満たす水素化粉末（後述）を用いたと考えられる。原料に上記範囲を満たす水素化粉末を用いることで、適度な大きさの成形圧力で水素化粉末を十分に塑性変形させられて、異方性磁石粉末の粒子同士を良好に結合することができ、強固な希土類磁石１とすることができる。磁性結合領域１３の平均粒径は、３０μｍ以上４００μｍ以下、更に５０μｍ以上３００μｍ以下とすることができる。この平均粒径の測定は、上述の異方性領域１２の場合と同様にすることができる。 -Shape and size The rare-earth magnet 1 includes a plurality of magnetic coupling regions 13. Each of the magnetic coupling regions 13 is typically formed of a material filled so as to fill a space created between the anisotropic regions 12 by plastic deformation in the manufacturing process (compression of the molding process). The Therefore, each magnetic coupling region 13 can take various shapes depending on the space. When the average particle size of the magnetic coupling region 13 is determined in the same manner as the measurement method of the average particle size described in the section “Shape” of the anisotropic region 12, the average particle size is 3 μm or more and 500 μm. The following are mentioned. When the average particle size of the magnetic coupling region 13 satisfies the above range, it is considered that hydrogenated powder (described later) having the average particle size satisfying the above range was used as the raw material. By using a hydrogenated powder satisfying the above range as a raw material, the hydrogenated powder can be sufficiently plastically deformed with a moderately large molding pressure, and the particles of anisotropic magnet powder can be bonded well together. A strong rare earth magnet 1 can be obtained. The average particle size of the magnetic coupling region 13 can be 30 μm or more and 400 μm or less, and further 50 μm or more and 300 μm or less. The average particle diameter can be measured in the same manner as in the case of the anisotropic region 12 described above.

・・含有量
希土類磁石１における磁性結合領域１３の存在割合が高いほど、異方性領域１２同士を強固に結合でき、強固な希土類磁石１とすることができる。しかし、希土類磁石１では、磁気特性に優れる異方性領域１２の存在割合を高くするほど磁気特性を高められる。そのため、磁性結合領域１３の存在割合は、体積割合で、５０％以下が好ましい。また、磁性結合領域１３の存在割合は、体積割合で、５％以上であれば、異方性領域１２同士を十分に結合できる上に、異方性領域１２の存在割合を十分に高められる（９５％以上とすることができる）。磁性結合領域１３の存在割合は、体積割合で、１５％以上３０％以下であると、異方性領域１２の存在による優れた磁気特性と、磁性結合領域１３の存在による強固な結合性とをバランスよく備えることができる。この存在割合の測定は、上述の異方性領域１２の場合と同様にすることができる。簡易的には、磁性結合領域１３の存在割合は、異方性領域１２を除いた残部とすることができる。 -Content The higher the existence ratio of the magnetic coupling region 13 in the rare earth magnet 1, the stronger the anisotropic regions 12 can be coupled to each other, and the stronger rare earth magnet 1 can be obtained. However, in the rare earth magnet 1, the magnetic properties can be enhanced as the ratio of the anisotropic regions 12 having excellent magnetic properties is increased. Therefore, the presence ratio of the magnetic coupling region 13 is preferably 50% or less by volume. Further, if the magnetic coupling region 13 is present at a volume ratio of 5% or more, the anisotropic regions 12 can be sufficiently coupled to each other, and the proportion of the anisotropic regions 12 can be sufficiently increased ( 95% or more). When the magnetic coupling region 13 is present in a volume ratio of 15% or more and 30% or less, excellent magnetic properties due to the presence of the anisotropic region 12 and strong bonding properties due to the presence of the magnetic coupling region 13 are obtained. Can be well-balanced. The measurement of the existence ratio can be performed in the same manner as in the case of the anisotropic region 12 described above. For simplicity, the proportion of the magnetic coupling region 13 can be the remainder excluding the anisotropic region 12.

・磁石相の含有割合
希土類磁石１は、異方性領域１２に加えて、磁性結合領域１３を備えることで、従来の樹脂ボンド磁石に比較して、磁石相の含有割合が高い。希土類磁石１の一例として、磁石相の含有割合が体積割合で７０％以上を満たす形態が挙げられる。磁石相の含有割合は、高いほど磁気特性に優れる希土類磁石１とすることができるため、７５体積％以上、更に８０体積％超、更には８２体積％以上が好ましい。 -Content ratio of magnet phase The rare earth magnet 1 includes a magnetic coupling region 13 in addition to the anisotropic region 12, so that the content ratio of the magnet phase is higher than that of a conventional resin bond magnet. As an example of the rare earth magnet 1, there is a form in which the content ratio of the magnet phase satisfies 70% or more by volume. The higher the content of the magnet phase, the more rare earth magnet 1 can have excellent magnetic properties. Therefore, it is preferably 75% by volume or more, more than 80% by volume, and more preferably 82% by volume or more.

希土類磁石１の磁石相の含有割合（体積割合）は、相対密度と実質的に等価である。相対密度は、真密度に対する見掛密度の比であり、（見掛密度／真密度）×１００で求められる。希土類磁石１の相対密度は、製造過程の中間品である粉末成形体（後述）の相対密度に依存し、成形後の熱処理に起因する熱収縮によって若干の増加がみられるものの、この粉末成形体の相対密度を実質的に維持する。従って、粉末成形体の相対密度を調整することで、希土類磁石１の相対密度、即ち磁石相の含有割合を所望の値（好ましくは７０体積％以上）にすることができる。希土類磁石１の見掛密度は、市販の密度測定装置を用いることで測定することができる。真密度は、例えば、異方性領域１２と磁性結合領域１３との混合物の成分分析を行い、組成に基づいて算出することができる。簡易的には、希土類磁石１の磁石相の含有割合（体積割合）は、上述のように観察面についてＳＥＭ観察を行い、ＳＥＭ画像における磁石相の面積割合を体積割合に換算した値（体積割合＝面積割合の１．５乗）とすることができる。   The content ratio (volume ratio) of the magnet phase of the rare earth magnet 1 is substantially equivalent to the relative density. The relative density is a ratio of the apparent density to the true density, and is obtained by (apparent density / true density) × 100. The relative density of the rare earth magnet 1 depends on the relative density of a powder molded body (described later) that is an intermediate product in the manufacturing process, and a slight increase is observed due to heat shrinkage caused by heat treatment after molding. The relative density of is substantially maintained. Therefore, by adjusting the relative density of the powder compact, the relative density of the rare earth magnet 1, that is, the content ratio of the magnet phase can be set to a desired value (preferably 70% by volume or more). The apparent density of the rare earth magnet 1 can be measured by using a commercially available density measuring device. For example, the true density can be calculated based on the composition by performing component analysis of the mixture of the anisotropic region 12 and the magnetic coupling region 13. For simplicity, the content ratio (volume ratio) of the magnet phase of the rare earth magnet 1 is obtained by performing SEM observation on the observation surface as described above, and converting the area ratio of the magnet phase in the SEM image into the volume ratio (volume ratio). = 1.5 of the area ratio).

・配向度
希土類磁石１は、上述のように磁石相の含有割合が高く、かつ磁石相の過半数が結晶磁気異方性を有する異方性領域１２であることから、磁石全体としての配向度も高い。希土類磁石１の一例として、配向度が７０％以上である形態が挙げられる。異方性領域１２自体の結晶配向度、異方性領域１２の含有量（存在割合）にもよるが、希土類磁石１の配向度が７５％以上、更に８０％以上、更には８５％以上である形態が挙げられる。ここでは、希土類磁石１の配向度は、残留磁束密度を用いて規定する。具体的には、希土類磁石１の配向方向に平行な方向の磁束密度Ｂｒと配向方向に直交する方向の残留磁束密度Ｂｒ⊥１、Ｂｒ⊥２との和に対する配向方向に平行な方向の残留磁束密度Ｂｒの比[Ｂｒ／｛Ｂｒ２＋（Ｂｒ⊥１）２＋（Ｂｒ⊥２）２｝１／２]×１００を希土類磁石１の配向度（％）とする。希土類磁石１の配向方向は、代表的には、磁場成形時における磁場の印加方向と平行な方向が挙げられる。配向方向を示す印などを希土類磁石１に付しておくと配向方向を判別し易い。 -Degree of orientation The rare earth magnet 1 has a high magnet phase content as described above, and the majority of the magnet phase is the anisotropic region 12 having crystal magnetic anisotropy. high. As an example of the rare earth magnet 1, there is a form in which the degree of orientation is 70% or more. Depending on the degree of crystal orientation of the anisotropic region 12 itself and the content (presence ratio) of the anisotropic region 12, the degree of orientation of the rare earth magnet 1 is 75% or more, further 80% or more, and further 85% or more. One form is mentioned. Here, the degree of orientation of the rare earth magnet 1 is defined using the residual magnetic flux density. Specifically, the residual magnetic flux in the direction parallel to the orientation direction with respect to the sum of the magnetic flux density Br in the direction parallel to the orientation direction of the rare earth magnet 1 and the residual magnetic flux density Br ⊥ 1 and Br ⊥ 2 in the direction orthogonal to the orientation direction. the density ratio of Br [Br / {Br 2 + (Br ⊥1) 2 + (Br ⊥2) 2} 1/2] × 100 and degree of orientation of the rare earth magnet 1 (%). The orientation direction of the rare earth magnet 1 is typically a direction parallel to the magnetic field application direction during magnetic field shaping. If a mark or the like indicating the orientation direction is attached to the rare earth magnet 1, the orientation direction can be easily determined.

・磁気特性
希土類磁石１は、上述のように磁石相の含有割合が従来の樹脂ボンド磁石よりも高いことから、同一材質の異方性磁石粉末を同量含む従来の樹脂ボンド磁石に比較して、磁気特性に優れる。また、希土類磁石１は、上述のように配向度が高いことからも、磁気特性に優れる。具体的には、最大エネルギー積（ＢＨ）ｍａｘや、残留磁束密度Ｂｒが高い。希土類磁石１の一例として、上述の配向度が７０％以上を満たす形態が挙げられる。希土類磁石１の別の例として、（ＢＨ）ｍａｘが９５ｋＪ／ｍ３以上を満たす形態が挙げられる。希土類磁石１の更に別の例として、Ｂｒが０．７０Ｔ以上を満たす形態が挙げられる。 -Magnetic characteristics Since the rare earth magnet 1 has a higher magnetic phase content than the conventional resin bonded magnet, as compared with the conventional resin bonded magnet containing the same amount of anisotropic magnet powder of the same material. Excellent magnetic properties. Moreover, since the rare earth magnet 1 has a high degree of orientation as described above, it is excellent in magnetic characteristics. Specifically, the maximum energy product (BH) max and the residual magnetic flux density Br are high. As an example of the rare earth magnet 1, a form in which the degree of orientation described above satisfies 70% or more can be given. Another example of the rare earth magnet 1 includes a form in which (BH) max satisfies 95 kJ / m 3 or more. Still another example of the rare earth magnet 1 is a form in which Br satisfies 0.70 T or more.

・その他
希土類磁石１は、その表面の少なくとも一部にめっき層（図示せず）を備えることができる。めっき層は、耐食層、装飾、放熱経路などの機能が期待できる。 Others The rare earth magnet 1 can be provided with a plating layer (not shown) on at least a part of its surface. The plating layer can be expected to have functions such as a corrosion-resistant layer, decoration, and heat dissipation path.

（希土類磁石の製造方法）
上述の希土類磁石１は、例えば、以下の準備工程と、成形工程と、結合工程とを備える実施形態の希土類磁石の製造方法によって製造される磁石素材１０に着磁することで製造することができる。以下、図１を参照して、各工程を順に説明する。 (Rare earth magnet manufacturing method)
The rare earth magnet 1 described above can be manufactured, for example, by magnetizing the magnet material 10 manufactured by the method of manufacturing a rare earth magnet of the embodiment including the following preparation process, molding process, and bonding process. . Hereinafter, with reference to FIG. 1, each process is demonstrated in order.

・準備工程
この工程では、異方性領域１２を形成する原料である異方性磁石粉末２０と、磁性結合領域１３を形成する原料である水素化粉末３０とを用意する（図１の上段参照）。異方性磁石粉末２０は、結晶磁気異方性を有する希土類磁石相からなる粉末であり、高い磁気特性を有する希土類磁石１を得るために用いる。但し、異方性磁石粉末２０は塑性変形性に劣ることから、実施形態の希土類磁石の製造方法では、塑性変形性に優れる水素化粉末３０を異方性磁石粉末２０の結合材として用いる。 Preparation Step In this step, an anisotropic magnet powder 20 that is a raw material for forming the anisotropic region 12 and a hydrogenated powder 30 that is a raw material for forming the magnetic coupling region 13 are prepared (see the upper part of FIG. 1). ). The anisotropic magnet powder 20 is a powder made of a rare earth magnet phase having crystal magnetic anisotropy, and is used to obtain the rare earth magnet 1 having high magnetic properties. However, since the anisotropic magnet powder 20 is inferior in plastic deformability, the hydrogenated powder 30 excellent in plastic deformability is used as a binder for the anisotropic magnet powder 20 in the rare earth magnet manufacturing method of the embodiment.

・・異方性磁石粉末
・・・組成
異方性磁石粉末２０の構成材料は、希土類元素と鉄族元素とを含む希土類−鉄系合金が挙げられる。より具体的には、希土類元素と、鉄族元素と、Ｂ及びＣから選択される少なくとも１種の元素とを含む希土類−鉄系合金が挙げられる。希土類−鉄系合金の詳細については、上述の異方性領域１２の「組成」の項と同様である。 .. Anisotropic magnet powder ... Composition The constituent material of the anisotropic magnet powder 20 includes a rare earth-iron-based alloy containing a rare earth element and an iron group element. More specifically, a rare earth-iron-based alloy containing a rare earth element, an iron group element, and at least one element selected from B and C can be given. The details of the rare earth-iron alloy are the same as those in the “composition” section of the anisotropic region 12 described above.

異方性磁石粉末２０の構成材料は、特に、Ｎｄ−Ｆｅ−Ｂ系合金、Ｎｄ−Ｆｅ−Ｃ系合金などのＮｄを含む組成であると、後述する結合工程での熱処理（脱水素処理）を受けた場合にも、結晶粒の成長を抑制して微細な結晶組織を維持し易い。その結果、微細結晶組織の異方性領域１２を備える磁石素材１０が得られ、ひいては微細結晶組織の異方性領域１２を備える希土類磁石１を製造することができる。この希土類磁石１は、結晶磁気異方性を有する上に、微細結晶組織である異方性領域１２の存在によって、高い残留磁束密度や高い最大エネルギー積に加えて、高い保磁力といった優れた磁気特性を有することができる。   When the material of the anisotropic magnet powder 20 has a composition containing Nd, such as an Nd—Fe—B alloy or Nd—Fe—C alloy, heat treatment (dehydrogenation treatment) in the bonding step described later In the case of receiving, it is easy to suppress the growth of crystal grains and maintain a fine crystal structure. As a result, a magnet material 10 having an anisotropic region 12 having a fine crystal structure is obtained, and as a result, the rare earth magnet 1 having an anisotropic region 12 having a fine crystal structure can be manufactured. The rare earth magnet 1 has excellent magnetic properties such as high coercive force in addition to high residual magnetic flux density and high maximum energy product due to the presence of the anisotropic region 12 which is a fine crystal structure in addition to the magnetocrystalline anisotropy. Can have properties.

・・・結晶磁気異方性
異方性磁石粉末２０は、結晶磁気異方性を有する粉末であり、ここでは、残留磁束密度Ｂｒが１．０Ｔ以上を満たす粉末とする。このような粉末は、例えば、ＨＤＤＲ（Ｈｙｄｒｏｇｅｎａｔｉｏｎ Ｄｅｃｏｍｐｏｓｉｔｉｏｎ Ｄｅｓｏｒｐｔｉｏｎ Ｒｅｃｏｍｂｉｎａｔｉｏｎ）処理であって、水素圧と温度とを特定の条件とするものを希土類−鉄系合金の粉末に施すことで製造することができる。このような特定のＨＤＤＲ処理の条件は、公知の条件を利用できる。上記希土類−鉄系合金の粉末は、例えば、ストリップキャスト法やアトマイズ法などの公知の粉末の製造方法を利用して製造することができる。又は、上記結晶磁気異方性を有する粉末は、例えば、メルトスパン法で作製した粉末に、ホットプレスとホットフォームなどの熱間加工とを組み合わせた処理を施すことで製造することができる。異方性磁石粉末２０の異方性（ここでは残留磁束密度Ｂｒ）は、製造条件を調整することで高めることができる。異方性磁石粉末２０の残留磁束密度Ｂｒは、異方性磁石粉末２０を樹脂に埋め込んだ埋め込み部材などを作製し、この埋め込み部材などに対して、試料振動型磁力計（ＶＳＭ）を利用して測定することが挙げられる。 ... Crystal magnetic anisotropy The anisotropic magnet powder 20 is a powder having crystal magnetic anisotropy. Here, the residual magnetic flux density Br is 1.0 T or more. Such a powder can be produced, for example, by subjecting a rare earth-iron-based alloy powder to HDDR (Hydrogen Deposition Decomposition Recombination) treatment with specific conditions of hydrogen pressure and temperature. As such specific HDDR processing conditions, known conditions can be used. The rare earth-iron-based alloy powder can be manufactured using, for example, a known powder manufacturing method such as a strip casting method or an atomizing method. Or the powder which has the said magnetocrystalline anisotropy can be manufactured by performing the process which combined hot processing, such as hot press and hot forming, to the powder produced by the melt span method, for example. The anisotropy (here, residual magnetic flux density Br) of the anisotropic magnet powder 20 can be increased by adjusting the manufacturing conditions. The residual magnetic flux density Br of the anisotropic magnet powder 20 is produced by using an embedded member in which the anisotropic magnet powder 20 is embedded in a resin and using a sample vibration magnetometer (VSM) for the embedded member. Measurement.

・・・組織
異方性磁石粉末２０を構成する希土類−鉄系合金は、多結晶体である（図１の上段、左図参照。破線円内は、異方性磁石粉末２０の粒子２１の組織を拡大して示す。）。各結晶粒が微細であれば、磁石素材１０中の異方性磁石粉末２０も微細結晶組織になることから、上述の微細結晶組織の異方性領域１２を備える希土類磁石１が得られて好ましい。例えば、異方性磁石粉末２０を構成する希土類−鉄系合金の平均結晶粒径は、７００ｎｍ以下が挙げられる。上記平均結晶粒径は、小さいほど磁気特性に優れる希土類磁石１を得易いことから、５００ｎｍ以下、更に３００ｎｍ以下が好ましい。結晶粒径は、上述の特定の条件のＨＤＤＲ処理を施すといった製造条件を調整することで、小さくすることができる。上記平均結晶粒径は、例えば、異方性磁石粉末２０を樹脂に埋め込んだ埋め込み部材を作製し、この埋め込み部材について、ＳＥＭなどの顕微鏡観察像を用いて異方性磁石粉末２０の粒子２１の結晶粒径を調べることで測定することができる。結晶粒径の算出方法は、上述の異方性領域２０の場合と同様にすることができる。 ... Structure The rare earth-iron-based alloy constituting the anisotropic magnet powder 20 is a polycrystalline body (see the upper diagram in FIG. 1 and the left diagram. The broken line circle shows the particles 21 of the anisotropic magnet powder 20. Enlarge the organization.) If each crystal grain is fine, the anisotropic magnet powder 20 in the magnet material 10 also has a fine crystal structure. Therefore, the rare earth magnet 1 having the above-described anisotropic region 12 of the fine crystal structure can be obtained, which is preferable. . For example, the average crystal grain size of the rare earth-iron alloy constituting the anisotropic magnet powder 20 is 700 nm or less. The average crystal grain size is preferably 500 nm or less, and more preferably 300 nm or less because the smaller the average crystal grain size, the easier it is to obtain the rare earth magnet 1 having excellent magnetic properties. The crystal grain size can be reduced by adjusting the manufacturing conditions such as the HDDR process under the specific conditions described above. The average crystal grain size is determined by, for example, producing an embedded member in which the anisotropic magnet powder 20 is embedded in a resin, and using the microscopic observation image such as SEM of the embedded member, the particles 21 of the anisotropic magnet powder 20 are formed. It can be measured by examining the crystal grain size. The method for calculating the crystal grain size can be the same as in the case of the anisotropic region 20 described above.

・・・形状及び大きさ
異方性磁石粉末２０が所望の大きさや形状となるように、異方性磁石粉末２０の製造過程の適宜な時期に粉砕や分級を行うことができる。異方性磁石粉末２０の形状が、例えば、真球状であれば、充填率（存在割合）を高め易くなり、凹凸形状などの表面積がより大きな異形状であれば、水素化粉末３０との接触面積を増大でき、強固な磁石素材１０（ひいては強固な希土類磁石１）を得易い。例えば、異方性磁石粉末２０の平均粒径は、３μｍ以上５００μｍ以下が挙げられる。上記平均粒径を３μｍ以上とすると、異方性磁石粉末２０の各粒子２１が、結合材となる水素化粉末３０の粒子３１と十分に接触することができ、強固な磁石素材１０が得られる。従って、強固な希土類磁石１を製造することができる。異方性磁石粉末２０が大き過ぎると、（ａ）粉末成形体１００の相対密度の低下を招く、（ｂ）圧縮成形時、塑性加工性に劣る異方性磁石粉末２０が割れる恐れがある、などが考えられることから、上記平均粒径は５００μｍ以下が好ましい。異方性磁石粉末２０の平均粒径は、３０μｍ以上４００μｍ以下、更に５０μｍ以上３００μｍ以下とすることができる。異方性磁石粉末２０の平均粒径及び後述する水素化粉末３０の平均粒径は、体積粒度分布における５０体積％粒径（Ｄ５０）とする。 ... Shape and size The anisotropic magnet powder 20 can be pulverized and classified at an appropriate time in the production process of the anisotropic magnet powder 20 so that the anisotropic magnet powder 20 has a desired size and shape. If the shape of the anisotropic magnet powder 20 is, for example, a true sphere, the filling rate (existence ratio) can be easily increased. If the shape of the anisotropic magnet powder 20 is an irregular shape having a larger surface area such as a concavo-convex shape, contact with the hydrogenated powder 30 is facilitated. The area can be increased, and it is easy to obtain a strong magnet material 10 (and thus a strong rare earth magnet 1). For example, the average particle diameter of the anisotropic magnet powder 20 is 3 μm or more and 500 μm or less. When the average particle diameter is 3 μm or more, each particle 21 of the anisotropic magnet powder 20 can sufficiently come into contact with the particles 31 of the hydrogenated powder 30 serving as a binder, and a strong magnet material 10 is obtained. . Therefore, the strong rare earth magnet 1 can be manufactured. If the anisotropic magnet powder 20 is too large, (a) the relative density of the powder compact 100 is reduced, and (b) at the time of compression molding, the anisotropic magnet powder 20 inferior in plastic workability may break. For example, the average particle size is preferably 500 μm or less. The average particle diameter of the anisotropic magnet powder 20 can be 30 μm or more and 400 μm or less, and further 50 μm or more and 300 μm or less. The average particle diameter of the anisotropic magnet powder 20 and the average particle diameter of the hydrogenated powder 30 described later are 50 volume% particle diameter (D50) in the volume particle size distribution.

・・水素化粉末
・・・組成
水素化粉末３０の構成材料は、後述する結合工程で脱水素処理を施すことで、脱水素及び再結合反応によって希土類元素と鉄族元素とを含む希土類−鉄系合金（代表的にはＮｄ−Ｆｅ−Ｂ系合金、Ｎｄ−Ｆｅ−Ｃ系合金）を形成可能な水素化合金が挙げられる。この水素化合金とは、希土類元素の水素化合物３２と、鉄族元素を含む相３４とが独立した相として存在する合金であり（図１の上段、右図参照）、換言すれば、水素不均化状態の組織を有する合金である。 ..Hydrogenated powder: Composition The constituent material of the hydrogenated powder 30 is a rare earth-iron containing a rare earth element and an iron group element by dehydrogenation and recombination reaction by performing a dehydrogenation process in a bonding step described later. Examples thereof include hydrogenated alloys capable of forming a base alloy (typically, an Nd—Fe—B alloy or an Nd—Fe—C alloy). This hydrogenated alloy is an alloy in which a rare earth element hydrogen compound 32 and a phase 34 containing an iron group element exist as independent phases (see the upper and right diagrams in FIG. 1). It is an alloy having a texture in a leveled state.

上記水素化合金中の希土類元素の水素化合物３２は、ＮｄＨ２などが挙げられる。Ｎｄを含む組成では、上記水素化合金中の希土類元素及び鉄族元素以外の元素として、Ｂ及びＣの少なくとも一方を含む形態が代表的である。ＢやＣは、代表的には、鉄硼化物や鉄炭化物などの鉄族元素との化合物として上記水素化合金中に存在する。鉄族元素を含む相３４は、Ｆｅなどの単体鉄族元素や、上述の鉄族元素を含む化合物などが挙げられる。上記水素化合金中のその他の元素として、上述の異方性領域１２の「組成」の項で述べた添加元素を含む形態が挙げられる。 Examples of the rare earth element hydrogen compound 32 in the hydrogenated alloy include NdH 2 . In the composition containing Nd, a form containing at least one of B and C is typical as an element other than the rare earth element and the iron group element in the hydrogenated alloy. B and C are typically present in the hydrogenated alloy as a compound with an iron group element such as iron boride or iron carbide. Examples of the phase 34 containing an iron group element include simple iron group elements such as Fe, and compounds containing the above iron group elements. Examples of the other elements in the hydrogenated alloy include a form containing the additive element described in the “composition” section of the anisotropic region 12 described above.

上記水素化合金中における希土類元素の水素化合物３２の含有量は、１０体積％以上４０体積％以下が挙げられる。換言すれば、上記水素化合金中における希土類元素の水素化合物３２を除く残部、即ち、鉄族元素を含む相３４の含有量は６０体積％以上が挙げられる。このような水素化合金は、希土類元素と鉄族元素とを含む希土類−鉄系合金に水素化処理を施すことで得られる。つまり、所望の組成のＮｄ−Ｆｅ−Ｂ系合金の粉末などを用意して、水素化処理を施すことで、水素化粉末３０が得られる。   The content of the rare earth element hydrogen compound 32 in the hydrogenated alloy is 10 volume% or more and 40 volume% or less. In other words, the remainder of the hydrogenated alloy excluding the rare earth element hydrogen compound 32, that is, the content of the phase 34 containing the iron group element is 60% by volume or more. Such a hydrogenated alloy can be obtained by subjecting a rare earth-iron alloy containing a rare earth element and an iron group element to a hydrogenation treatment. That is, the hydrogenated powder 30 is obtained by preparing a powder of an Nd—Fe—B alloy having a desired composition and performing a hydrogenation treatment.

水素化処理の条件は、例えば、以下が挙げられる。雰囲気は、水素を含む雰囲気とする。具体的には、水素雰囲気、水素と、アルゴンや窒素といった不活性ガスとの混合雰囲気が挙げられる。処理温度は、用意した合金の水素不均化温度以上が挙げられる。材質にもよるが、処理温度は、６００℃以上、更に６５０℃以上が挙げられる。好ましくは、処理温度は、７００℃以上、更に７５０℃以上、１１００℃以下、更に９００℃以下が挙げられる。保持時間は、０．５時間以上５時間以下、更に１時間以上４時間以下が挙げられる。特許文献２に記載される条件やその他の公知のＨＤ条件を利用することができる。   Examples of the conditions for the hydrogenation treatment include the following. The atmosphere is an atmosphere containing hydrogen. Specific examples include a hydrogen atmosphere and a mixed atmosphere of hydrogen and an inert gas such as argon or nitrogen. The treatment temperature may be higher than the hydrogen disproportionation temperature of the prepared alloy. Although depending on the material, the processing temperature is 600 ° C. or higher, and further 650 ° C. or higher. Preferably, the treatment temperature is 700 ° C. or higher, further 750 ° C. or higher, 1100 ° C. or lower, and further 900 ° C. or lower. As for holding time, 0.5 hour or more and 5 hours or less, Furthermore, 1 hour or more and 4 hours or less are mentioned. The conditions described in Patent Document 2 and other known HD conditions can be used.

水素化粉末３０の構成材料は、特に、Ｎｄ−Ｆｅ−Ｂ系合金やＮｄ−Ｆｅ−Ｃ系合金といったＮｄを含む組成であることが好ましい。この場合、後述する成形後に脱水素処理を施す結合工程を経て得られた再結合合金は、磁石相（Ｎｄ−Ｆｅ−Ｂ系合金など）である。そのため、結合工程を経て得られた磁石素材１０に着磁することで希土類磁石１が得られる。この点から、この形態は、工程数が少なく、磁気特性に優れる希土類磁石１を生産性よく製造できるといえる。   The constituent material of the hydrogenated powder 30 is particularly preferably a composition containing Nd such as an Nd—Fe—B alloy or an Nd—Fe—C alloy. In this case, the recombined alloy obtained through a bonding step in which dehydrogenation is performed after molding, which will be described later, is a magnet phase (Nd—Fe—B alloy, etc.). Therefore, the rare earth magnet 1 is obtained by magnetizing the magnet material 10 obtained through the joining process. From this point, it can be said that in this embodiment, the rare earth magnet 1 having a small number of steps and excellent magnetic characteristics can be manufactured with high productivity.

・・・形状及び大きさ
水素化粉末３０が所望の大きさや形状となるように、水素化粉末３０の製造過程の適宜な時期に粉砕や分級を行うことができる。特に、上記水素化処理後に粉砕などを行うと、小さ過ぎる粉末が少なく、成形し易い大きさの粉末を効率よく得られて好ましい。例えば、水素化粉末３０の平均粒径は、３μｍ以上５００μｍ以下が挙げられる。上記平均粒径を３μｍ以上とすると、異方性磁石粉末２０の各粒子２１の周囲に満遍なく、水素化粉末３０の粒子３１を存在させられて、両粉末の粒子２１，３１同士が十分に接触することができ、異方性磁石粉末２０の粒子２１同士を水素化粉末３０の粒子３１によって十分に結合できる。従って、強固な磁石素材１０が得られることから、ひいては強固な希土類磁石１を製造することができる。また、上記平均粒径を３μｍ以上とすることで、（ａ）酸化し難い、（ｂ）成形し易い、（ｃ）取り扱い易いといった利点がある。水素化粉末３０が大き過ぎると、粉末成形体１００の相対密度の低下などが考えられることから、上記平均粒径は５００μｍ以下が好ましい。水素化粉末３０の平均粒径は、３０μｍ以上４００μｍ以下、更に５０μｍ以上３００μｍ以下とすることができる。 ... Shape and size The hydrogenated powder 30 can be pulverized and classified at an appropriate time in the production process of the hydrogenated powder 30 such that the hydrogenated powder 30 has a desired size and shape. In particular, it is preferable to perform pulverization after the hydrogenation treatment because a powder having a size that is easy to be formed can be efficiently obtained because there are few powders that are too small. For example, the average particle diameter of the hydrogenated powder 30 is 3 μm or more and 500 μm or less. When the average particle size is 3 μm or more, the particles 31 of the hydrogenated powder 30 are allowed to exist evenly around the particles 21 of the anisotropic magnet powder 20, and the particles 21 and 31 of both powders are in sufficient contact with each other. The particles 21 of the anisotropic magnet powder 20 can be sufficiently bonded by the particles 31 of the hydrogenated powder 30. Accordingly, since the strong magnet material 10 is obtained, the strong rare earth magnet 1 can be manufactured. Further, by setting the average particle size to 3 μm or more, there are advantages that (a) it is difficult to oxidize, (b) it is easy to mold, and (c) it is easy to handle. If the hydrogenated powder 30 is too large, a decrease in the relative density of the powder compact 100 may be considered, and thus the average particle size is preferably 500 μm or less. The average particle size of the hydrogenated powder 30 can be 30 μm or more and 400 μm or less, and further 50 μm or more and 300 μm or less.

異方性磁石粉末２０の大きさ（平均粒径）と、水素化粉末３０の大きさ（平均粒径）とは、同じとすることもできるし、異ならせることもできる。両粉末２０，３０の大きさが同程度であると（平均粒径の差が５０μｍ以内程度）、均一的に混合し易いと考えられる。   The size (average particle size) of the anisotropic magnet powder 20 and the size (average particle size) of the hydrogenated powder 30 can be the same or different. If the sizes of both powders 20 and 30 are about the same (difference in average particle diameter is about 50 μm or less), it is considered that mixing is easy.

・・配合割合
次の成形工程では、異方性磁石粉末２０と水素化粉末３０とを混合した混合粉末１１０を用いる。配合割合が所望の値となるように、各粉末２０，３０の量を調整する。特に、混合粉末１１０における異方性磁石粉末２０の配合割合が多いほど、異方性磁石粉末２０の存在割合が高い磁石素材１０が得られる。ひいては、異方性磁石粉末２０から構成される異方性領域１２の存在割合が高い希土類磁石１が得られる。従って、異方性磁石粉末２０の配合割合は、過半数、具体的には質量割合で５０％超とすることが好ましい。異方性磁石粉末２０の配合割合は、高いほど異方性領域１２の存在割合が高くなり、磁石特性に優れる希土類磁石１が得られることから、質量割合で、６０％以上、更に７０％以上、更には７５％以上が好ましい。異方性磁石粉末２０の配合割合が大き過ぎると、結合材となる水素化粉末２０が相対的に少なくなって、異方性磁石粉末２０の粒子２１同士が十分に結合できなくなる恐れがある。従って、異方性磁石粉末２０の配合割合は、９５％以下が好ましく、９０％以下がより好ましい。 .. Mixing ratio In the next molding step, a mixed powder 110 obtained by mixing the anisotropic magnet powder 20 and the hydrogenated powder 30 is used. The amount of each powder 20, 30 is adjusted so that the blending ratio becomes a desired value. In particular, the larger the blending ratio of the anisotropic magnet powder 20 in the mixed powder 110, the higher the magnetic material 10 with the anisotropic magnet powder 20 present. As a result, the rare earth magnet 1 having a high presence ratio of the anisotropic region 12 composed of the anisotropic magnet powder 20 is obtained. Therefore, the blending ratio of the anisotropic magnet powder 20 is preferably a majority, specifically, more than 50% by mass ratio. As the blending ratio of the anisotropic magnet powder 20 is higher, the presence ratio of the anisotropic region 12 is higher, and the rare earth magnet 1 having excellent magnet characteristics can be obtained. Therefore, the mass ratio is 60% or more, and further 70% or more. Furthermore, 75% or more is preferable. If the blending ratio of the anisotropic magnet powder 20 is too large, the hydrogenated powder 20 serving as a binder becomes relatively small, and the particles 21 of the anisotropic magnet powder 20 may not be sufficiently bonded to each other. Therefore, the blending ratio of the anisotropic magnet powder 20 is preferably 95% or less, and more preferably 90% or less.

・成形工程
この工程では、異方性磁石粉末２０と水素化粉末３０とを混合した混合粉末１１０を用意し、この混合粉末１１０を圧縮成形して、粉末成形体１００を得る。混合粉末１１０は、水素化粉末３０を含むことから、良好に成形できる。水素化粉末３０は、Ｆｅ成分といった柔らかい鉄族元素を含む相３４を６０体積％以上含む水素化合金からなることで、塑性変形性に優れるからである。特に、この工程では、塑性変形した水素化粉末３０によって、異方性磁石粉末２０の粒子２１同士を結合しながら、混合粉末１１０を緻密化していく。 -Molding process In this process, the mixed powder 110 which mixed the anisotropic magnet powder 20 and the hydrogenated powder 30 is prepared, and this mixed powder 110 is compression-molded, and the powder compact 100 is obtained. Since the mixed powder 110 includes the hydrogenated powder 30, it can be molded well. This is because the hydrogenated powder 30 is made of a hydrogenated alloy containing 60 vol% or more of a phase 34 containing a soft iron group element such as an Fe component, and thus has excellent plastic deformability. In particular, in this step, the mixed powder 110 is densified while the particles 21 of the anisotropic magnet powder 20 are bonded to each other by the plastically deformed hydrogenated powder 30.

粉末成形体１００の相対密度が大きいほど、磁石相の含有割合が高く、緻密な希土類磁石１が得られる。従って、この工程では、粉末成形体１００の相対密度をできるだけ高めることが好ましい。具体的には、粉末成形体１００の相対密度を７０％以上とすることが好ましく、７５％以上、更に８０％超、更には８２％以上がより好ましい。実施形態の希土類磁石の製造方法では、塑性加工性に劣る異方性磁石粉末２０（好ましくは混合粉末１１０の過半数）を用いていながら、金型成形によって異方性磁石粉末２０を多く含み、かつ高密度な粉末成形体１００を製造することができる。   The higher the relative density of the powder compact 100, the higher the content ratio of the magnet phase, and the dense rare earth magnet 1 can be obtained. Therefore, in this step, it is preferable to increase the relative density of the powder compact 100 as much as possible. Specifically, the relative density of the powder compact 100 is preferably 70% or more, more preferably 75% or more, further more than 80%, and more preferably 82% or more. In the rare earth magnet manufacturing method of the embodiment, while using the anisotropic magnet powder 20 (preferably the majority of the mixed powder 110) having inferior plastic workability, a large amount of the anisotropic magnet powder 20 is formed by molding, and A high-density powder compact 100 can be manufactured.

粉末成形体１００の相対密度は、以下のように測定する。粉末成形体の見掛密度は、市販の密度測定装置を用いることで測定することができる。粉末成形体の真密度は、異方性磁石粉末２０の密度と、水素化粉末３０の密度と、それぞれの配合割合とを用いて算出することができる。各粉末２０，３０の密度は、組成に基づいて算出することができる。   The relative density of the powder compact 100 is measured as follows. The apparent density of the powder compact can be measured by using a commercially available density measuring device. The true density of the powder compact can be calculated by using the density of the anisotropic magnet powder 20, the density of the hydrogenated powder 30, and the blending ratio thereof. The density of each powder 20, 30 can be calculated based on the composition.

成形圧力が大きいほど、粉末成形体１００の相対密度が大きく、空隙が少なくなる傾向にある。所望の相対密度となるように成形圧力を調整するとよい。成形圧力は、例えば、５８８ＭＰａ（６ｔｏｎ／ｃｍ２）以上１９６０ＭＰａ（２０ｔｏｎ／ｃｍ２）以下が挙げられる。 As the molding pressure increases, the relative density of the powder compact 100 increases and voids tend to decrease. The molding pressure may be adjusted so that a desired relative density is obtained. Examples of the molding pressure include 588 MPa (6 ton / cm 2 ) or more and 1960 MPa (20 ton / cm 2 ) or less.

実施形態の希土類磁石の製造方法では、特に、混合粉末１１０の成形を磁場印加中で行う。こうすることで、従来の樹脂ボンド磁石の製造過程と同様に、結晶磁気異方性を有する異方性磁石粉末２０の各粒子２１は、磁場の印加方向に従って回転などの移動を行って金型５０内で配列する。そのため、配向性に優れる粉末成形体１００が得られ、ひいては配向性に優れる希土類磁石１（異方性磁石）を製造できる。即ち、実施形態の希土類磁石の製造方法では、後述する脱水素処理時に強磁場を印加しなくても、配向性に優れる希土類磁石１を製造できることから、脱水素処理を行う際の制御などが容易である。また、磁場印加中で成形して配向性を高める場合には、異方性磁石粉末２０の各粒子２１が斑なく配列し易いことから、配向性をより高め易い。これらの点から、実施形態の希土類磁石の製造方法では、磁気特性に優れる希土類磁石１を生産性よく製造できるといえる。   In the rare earth magnet manufacturing method of the embodiment, in particular, the mixed powder 110 is formed while a magnetic field is applied. By doing so, each particle 21 of the anisotropic magnet powder 20 having crystal magnetic anisotropy is moved by rotation or the like in accordance with the direction of application of the magnetic field in the same manner as in the manufacturing process of the conventional resin bonded magnet. Arrange within 50. Therefore, a powder compact 100 having excellent orientation can be obtained, and as a result, the rare earth magnet 1 (anisotropic magnet) having excellent orientation can be produced. That is, in the rare earth magnet manufacturing method according to the embodiment, since the rare earth magnet 1 having excellent orientation can be manufactured without applying a strong magnetic field during the dehydrogenation process described later, it is easy to control the dehydrogenation process. It is. Moreover, when shape | molding in the application of a magnetic field and improving orientation, since each particle | grain 21 of the anisotropic magnet powder 20 is easy to arrange without unevenness, it is easy to improve orientation. From these points, it can be said that the rare earth magnet 1 having excellent magnetic properties can be produced with high productivity in the method for producing a rare earth magnet of the embodiment.

印加磁場の大きさは、０．５Ｔ以上１０Ｔ以下程度、更に１．５Ｔ以上１０Ｔ以下程度が挙げられる。印加磁場が大きいほど、配向性を高められ、磁気特性に優れる希土類磁石１が得られる。磁場の印加には、常電導コイルを備える常電導磁石、超電導コイルを備える超電導磁石のいずれも利用できる。磁場の印加方向は、適宜選択することができる。図１の上方の中段では、磁場の印加方向を一点鎖線矢印で示している。ここでは、磁場の印加方向は、圧縮方向（ここでは上下方向）に直交する場合を例示している。   The magnitude of the applied magnetic field is about 0.5T to 10T, and further about 1.5T to 10T. The larger the applied magnetic field, the higher the orientation and the rare earth magnet 1 having excellent magnetic properties. For the application of the magnetic field, either a normal conducting magnet having a normal conducting coil or a superconducting magnet having a superconducting coil can be used. The application direction of the magnetic field can be appropriately selected. In the upper middle part of FIG. 1, the direction in which the magnetic field is applied is indicated by a one-dot chain line arrow. Here, the case where the application direction of the magnetic field is orthogonal to the compression direction (the vertical direction here) is illustrated.

異方性磁石粉末２０と水素化粉末３０との混合には、適宜な混合機を用いることができる。成形には、所望の形状の金型５０（図１の上方の中段参照）を利用するとよい。金型５０は、代表的には、貫通孔を有するダイ５２と、ダイ５２の内周面と共に成形空間を形成し、上記貫通孔に挿入して原料粉末（ここでは混合粉末１１０）を圧縮成形する一対のパンチ５４，５６とを備える構成が代表的である。貫通孔を有する粉末成形体１００を成形する場合には、ダイ５２の貫通孔に挿入配置されるロッド（図示せず）を利用する。成形時の潤滑性を高めるために、混合粉末１１０に潤滑剤を適宜混合したり、金型５０の内面に潤滑剤を塗布したりすることができる。金型５０の周囲には、磁場を印加するための磁石（図示せず）を配置する。   An appropriate mixer can be used for mixing the anisotropic magnet powder 20 and the hydrogenated powder 30. For molding, a mold 50 having a desired shape (see the upper middle part in FIG. 1) may be used. The mold 50 typically forms a molding space together with a die 52 having a through-hole and an inner peripheral surface of the die 52, and is inserted into the through-hole to compress a raw material powder (here, mixed powder 110). A configuration including a pair of punches 54 and 56 is typical. When molding the powder molded body 100 having a through hole, a rod (not shown) inserted into the through hole of the die 52 is used. In order to improve the lubricity at the time of molding, a lubricant can be appropriately mixed with the mixed powder 110, or a lubricant can be applied to the inner surface of the mold 50. A magnet (not shown) for applying a magnetic field is disposed around the mold 50.

成形工程の雰囲気は、非酸化性雰囲気や低酸素雰囲気（酸素が２０体積％未満）とすると、混合粉末１１０の酸化を防止できて好ましい。一方、大気雰囲気とすると、雰囲気制御が容易であり、作業性に優れる。   The atmosphere of the molding process is preferably a non-oxidizing atmosphere or a low-oxygen atmosphere (oxygen is less than 20% by volume), which can prevent oxidation of the mixed powder 110. On the other hand, when the atmosphere is used, the atmosphere control is easy and the workability is excellent.

・結合工程
この工程では、作製した粉末成形体１００に脱水素処理を施して（図１の下方の中段参照）、水素化粉末３０を構成する水素化合金を希土類−鉄系合金などの再結合合金に変化させる。この工程を経ることで、異方性磁石粉末２０の粒子２１が、水素化合金でなく、再結合合金によって結合された磁石素材１０を得ることができる。水素化粉末３０の組成にもよるが、この結合工程を経ることで、粉末成形体１００を構成していた一部の材料（ここでは水素化粉末３０）が磁石相（例えば、Ｎｄ−Ｆｅ−Ｂ系合金などの再結合合金）に変化して、実質的に磁石相のみで構成される磁石素材１０が得られる。つまり、実施形態の希土類磁石の製造方法では、特定の製造過程を経て磁石相に変化するものを原料に用いることで、従来の樹脂ボンド磁石と類似の製造過程（原料の準備、磁場成形、熱処理（樹脂の硬化など））でありながら、磁石相の含有割合が遥かに高く、磁気特性に優れる希土類磁石１を製造できる点で、工業的意義が高いといえる。 Bonding step In this step, the produced powder compact 100 is subjected to dehydrogenation treatment (see the middle stage in the lower part of FIG. 1), and the hydrogenated alloy constituting the hydrogenated powder 30 is rebonded to a rare earth-iron alloy or the like. Change to alloy. By passing through this process, the magnet raw material 10 in which the particles 21 of the anisotropic magnet powder 20 are bonded by a recombination alloy instead of a hydrogenated alloy can be obtained. Depending on the composition of the hydrogenated powder 30, through this bonding step, a part of the material constituting the powder molded body 100 (here, the hydrogenated powder 30) becomes a magnetic phase (for example, Nd—Fe—). It is changed to a recombination alloy such as a B-based alloy), and a magnet material 10 substantially composed only of a magnet phase is obtained. That is, in the rare earth magnet manufacturing method of the embodiment, by using a material that changes to a magnet phase through a specific manufacturing process as a raw material, a manufacturing process similar to a conventional resin bond magnet (preparation of raw material, magnetic field molding, heat treatment) However, it can be said that the content of the magnet phase is much higher and the rare-earth magnet 1 having excellent magnetic properties can be manufactured.

脱水素処理の条件は、例えば、以下が挙げられる。雰囲気は、非水素雰囲気とする。具体的には、不活性雰囲気（例えば、アルゴンや窒素といった不活性ガス雰囲気）、減圧雰囲気（例えば、標準の大気圧よりも圧力が低い真空雰囲気)が挙げられる。特に、減圧雰囲気は、希土類元素の水素化合物が残存し難くて好ましい。減圧雰囲気では、真空度は１００Ｐａ以下、最終真空度は１０Ｐａ以下、更に１Ｐａ以下が挙げられる。処理温度は、水素化合金の再結合温度以上が挙げられる。材質にもよるが、処理温度は、６００℃以上、更に７００℃以上が挙げられる。処理温度が低いほど、再結合合金の結晶の成長を抑制して微細な結晶組織が得られることから、処理温度は１０００℃以下が好ましい。より好ましくは、処理温度は、７３０℃以上９００℃以下、更に７５０℃以上８５０℃以下が挙げられる。保持時間は、１０分以上６００分（１０時間）以下、更に３０分（０．５時間）以上４８０分（８時間）以下が挙げられる。特許文献２に記載される条件やその他の公知のＤＲ処理の条件を利用することができる。また、脱水素処理は、粉末成形体１００に強磁場（例えば、４Ｔ以上）を印加した状態で行うことができる。こうすることで、再結合合金の配向性を高められ、ひいては磁性結合領域１３の配向性を高められる。   Examples of the dehydrogenation conditions include the following. The atmosphere is a non-hydrogen atmosphere. Specifically, an inert atmosphere (for example, an inert gas atmosphere such as argon or nitrogen) and a reduced pressure atmosphere (for example, a vacuum atmosphere whose pressure is lower than the standard atmospheric pressure) can be used. In particular, a reduced pressure atmosphere is preferable because rare earth hydrogen compounds hardly remain. In a reduced pressure atmosphere, the degree of vacuum is 100 Pa or less, the final degree of vacuum is 10 Pa or less, and further 1 Pa or less. Examples of the treatment temperature include the recombination temperature of the hydrogenated alloy. Although depending on the material, the processing temperature is 600 ° C. or higher, and 700 ° C. or higher. The processing temperature is preferably 1000 ° C. or lower because the lower the processing temperature, the more the crystal growth of the recombined alloy is suppressed and a fine crystal structure is obtained. More preferably, processing temperature is 730 degreeC or more and 900 degrees C or less, Furthermore, 750 degreeC or more and 850 degrees C or less are mentioned. The holding time may be 10 minutes or more and 600 minutes (10 hours) or less, and further 30 minutes (0.5 hours) or more and 480 minutes (8 hours) or less. The conditions described in Patent Document 2 and other known DR processing conditions can be used. Further, the dehydrogenation treatment can be performed in a state where a strong magnetic field (for example, 4 T or more) is applied to the powder compact 100. By doing so, the orientation of the recombination alloy can be enhanced, and consequently the orientation of the magnetic coupling region 13 can be enhanced.

上述の準備工程、成形工程、結合工程を経ることで、例えば、以下の希土類磁石が得られる。この希土類磁石は、希土類元素を含み、結晶磁気異方性を有する複数の異方性磁石粒子と、希土類元素と鉄族元素とを含む希土類−鉄系合金から構成され、前記異方性磁石粒子同士を結合する磁性結合領域とを備え、前記磁性結合領域の結晶配向度は、前記異方性磁石粒子の結晶配向度よりも低い。   For example, the following rare earth magnets can be obtained through the above preparation process, molding process, and bonding process. The rare earth magnet includes a plurality of anisotropic magnet particles including a rare earth element and having magnetocrystalline anisotropy, and a rare earth-iron-based alloy including a rare earth element and an iron group element. A magnetic coupling region that couples each other, and the crystal orientation of the magnetic coupling region is lower than the crystal orientation of the anisotropic magnet particles.

［試験例１］
希土類元素を含み、結晶磁気異方性を有する異方性磁石粉末と、種々の結合材とを用いて、Ｎｄ−Ｆｅ−Ｂ系合金の組成を有する希土類磁石を作製し、磁気特性を調べた。 [Test Example 1]
A rare earth magnet having a composition of an Nd-Fe-B alloy was prepared using anisotropic magnet powder containing rare earth elements and having magnetocrystalline anisotropy and various binders, and the magnetic properties were examined. .

異方性磁石粉末として、Ｎｄ−Ｆｅ−Ｂ合金からなり、平均粒径（Ｄ５０）が１５０μｍ程度の多結晶粉末を用意する。この異方性磁石粉末の残留磁束密度Ｂｒは１．３１Ｔ（≧１．０Ｔ）であり、結晶磁気異方性を有する粉末である。また、異方性磁石粉末を構成するＮｄ−Ｆｅ−Ｂ合金の平均結晶粒径は、３００ｎｍである（≦７００ｎｍ）。この異方性磁石粉末は、市販品である。   As an anisotropic magnet powder, a polycrystalline powder made of an Nd—Fe—B alloy and having an average particle diameter (D50) of about 150 μm is prepared. The anisotropic magnetic powder has a residual magnetic flux density Br of 1.31 T (≧ 1.0 T) and is a powder having crystal magnetic anisotropy. The average crystal grain size of the Nd—Fe—B alloy constituting the anisotropic magnet powder is 300 nm (≦ 700 nm). This anisotropic magnet powder is a commercial product.

試料Ｎｏ．１−１〜Ｎｏ．１−５では、結合材に、希土類元素の水素化合物と鉄族元素とを含む水素化合金からなる水素化粉末を用いる。この結合材は、以下のようにして作製する。粒度が０．５ｍｍ〜３０ｍｍであるＮｄ−Ｆｅ−Ｂ合金のインゴット（小片）を準備し、水素雰囲気中、８５０℃×３時間の熱処理（水素化処理）を実施する。上記水素化処理を行って得られた水素化合金を超硬合金製の乳鉢を用いて粉砕し、平均粒径（Ｄ５０）が１５０μｍ程度の水素化粉末を結合材として用意する。   Sample No. 1-1-No. In 1-5, a hydrogenated powder made of a hydrogenated alloy containing a rare earth element hydrogen compound and an iron group element is used as the binder. This binder is produced as follows. An Nd—Fe—B alloy ingot (small piece) having a particle size of 0.5 mm to 30 mm is prepared, and heat treatment (hydrogenation treatment) is performed at 850 ° C. for 3 hours in a hydrogen atmosphere. The hydrogenated alloy obtained by performing the above hydrogenation treatment is pulverized using a cemented carbide mortar, and a hydrogenated powder having an average particle size (D50) of about 150 μm is prepared as a binder.

そして、試料Ｎｏ．１−１〜Ｎｏ．１−５では、用意した異方性磁石粉末と、水素化粉末とを異方性磁石粉末の配合割合が５０質量％〜９０質量％となるように配合し、窒素雰囲気中、Ｖ型ミキサーを用いて３０分間混合して、混合粉末を準備する。表１に、異方性磁石粉末の配合割合（質量％）を示す。   And sample no. 1-1-No. In 1-5, the prepared anisotropic magnet powder and the hydrogenated powder are blended so that the blending ratio of the anisotropic magnet powder is 50% by mass to 90% by mass. Use to mix for 30 minutes to prepare mixed powder. Table 1 shows the blending ratio (mass%) of the anisotropic magnet powder.

用意した試料Ｎｏ．１−１〜Ｎｏ．１−５の混合粉末を１．５Ｔの磁場印加中で成形して、１０ｍｍ×１０ｍｍ×１０ｍｍの柱状の粉末成形体を作製する。成形圧力は約９８０ＭＰａ（１０ｔｏｎ／ｃｍ２）とする。作製した粉末成形体の相対密度を表１に示す。相対密度（％）は、粉末成形体の見掛密度を市販の密度測定装置によって測定し、粉末成形体の真密度をＮｄ−Ｆｅ−Ｂ合金の真密度である７．５ｇ／ｃｍ３として、（見掛密度／真密度）×１００を算出して求める。その結果、試料Ｎｏ．１−１〜Ｎｏ．１−５の粉末成形体の相対密度はいずれも、表１に示すように７０％以上である。試料Ｎｏ．１−１〜Ｎｏ．１−５の粉末成形体の相対密度がこのように高い理由は、水素化粉末が塑性変形性に優れることで、異方性磁石粉末の粒子間に変形した水素化粉末が十分に介在して緻密化できたため、と考えられる。 Sample No. prepared 1-1-No. The 1-5 mixed powder is molded while applying a magnetic field of 1.5 T to produce a columnar powder compact of 10 mm × 10 mm × 10 mm. The molding pressure is about 980 MPa (10 ton / cm 2 ). The relative density of the produced powder compact is shown in Table 1. The relative density (%) is determined by measuring the apparent density of the powder compact with a commercially available density measuring device, and setting the true density of the powder compact to 7.5 g / cm 3 which is the true density of the Nd—Fe—B alloy. It is obtained by calculating (apparent density / true density) × 100. As a result, sample no. 1-1-No. As shown in Table 1, the relative density of 1-5 powder compacts is 70% or more. Sample No. 1-1-No. The reason why the relative density of the powder compact of 1-5 is so high is that the hydrogenated powder is excellent in plastic deformability, and the deformed hydrogenated powder is sufficiently interposed between the particles of the anisotropic magnet powder. This is thought to be due to densification.

得られた試料Ｎｏ．１−１〜Ｎｏ．１−５の粉末成形体に、真空中（最終真空度１０Ｐａ以下）、８００℃×３時間の熱処理（脱水素処理）を実施する。上記脱水素処理を行って得られた熱処理材について、任意の複数の箇所（気孔部分を除く）の成分分析を行ったところ、いずれもＮｄ−Ｆｅ−Ｂ合金であった。このことから、Ｎｄ−Ｆｅ−Ｂ合金の異方性磁石粉末と、ＮｄＨ２とＦｅとを含む水素化合金の水素化粉末とを主体とする粉末成形体に脱水素処理を施すことで、実質的にＮｄ−Ｆｅ−Ｂ合金で構成される磁石素材が得られることが確認できた。組成の分析は、磁石素材（熱処理材）の断面をＸ線回折などすることによって行うことができる。 The obtained sample No. 1-1-No. The powder molded body of 1-5 is subjected to heat treatment (dehydrogenation treatment) at 800 ° C. for 3 hours in a vacuum (final vacuum degree of 10 Pa or less). About the heat processing material obtained by performing the said dehydrogenation, when the component analysis of arbitrary several places (except a pore part) was conducted, all were Nd-Fe-B alloys. From this, by performing dehydrogenation treatment on the powder compact mainly composed of anisotropic magnet powder of Nd—Fe—B alloy and hydrogenated powder of hydrogenated alloy containing NdH 2 and Fe, In particular, it was confirmed that a magnet material composed of an Nd—Fe—B alloy was obtained. Analysis of the composition can be performed by X-ray diffraction or the like of the cross section of the magnet material (heat treatment material).

比較として、結合材に、樹脂を用いた試料Ｎｏ．１−１０１を以下のように作製する。上述の異方性磁石粉末（平均結晶粒径が３００ｎｍのＮｄ−Ｆｅ−Ｂ合金からなり、残留磁束密度Ｂｒが１．３１Ｔ、平均粒径Ｄ５０が約１５０μｍの多結晶粉末）とエポキシ樹脂とを用意して、表１に示す配合割合で混合する。この樹脂を含む混合粉末を１．５Ｔの磁場印加中で成形する。成形圧力は約６８６ＭＰａ（７ｔｏｎ／ｃｍ２）、金型温度は１５０℃、アルゴン（Ａｒ）雰囲気下とする。成形後、室温まで冷却して、１０ｍｍ×１０ｍｍ×１０ｍｍの柱状の樹脂ボンド磁石素材を作製する。 As a comparison, sample No. using a resin as the binder was used. 1-101 is produced as follows. The above-mentioned anisotropic magnet powder (made of an Nd—Fe—B alloy having an average crystal grain size of 300 nm, a polycrystalline powder having a residual magnetic flux density Br of 1.31 T and an average grain size D50 of about 150 μm) and an epoxy resin Prepare and mix at the blending ratio shown in Table 1. The mixed powder containing the resin is molded while applying a 1.5 T magnetic field. The molding pressure is about 686 MPa (7 ton / cm 2 ), the mold temperature is 150 ° C., and an argon (Ar) atmosphere. After molding, it is cooled to room temperature to produce a 10 mm × 10 mm × 10 mm columnar resin bonded magnet material.

作製した試料Ｎｏ．１−１〜Ｎｏ．１−５の磁石素材及び試料Ｎｏ．１−１０１の樹脂ボンド磁石素材について、磁石相の存在割合（体積割合）を調べた。その結果を表１に示す。また、これらの磁石素材及び樹脂ボンド磁石素材について、密度を調べた。その結果も表１に示す。密度（ｇ／ｃｍ３）は、市販の密度測定装置を用いて測定する。 The prepared sample No. 1-1-No. 1-5 magnet material and sample no. For the resin-bonded magnet material 1-101, the existence ratio (volume ratio) of the magnet phase was examined. The results are shown in Table 1. Moreover, the density was investigated about these magnet raw materials and resin bond magnet raw materials. The results are also shown in Table 1. The density (g / cm 3 ) is measured using a commercially available density measuring device.

試料Ｎｏ．１−１〜Ｎｏ．１−５の磁石素材について、磁石相の存在割合（体積割合）は、磁石素材の断面をとってＳＥＭ観察を行い、ＳＥＭ画像における磁石相の面積割合を体積割合に換算して求める（体積割合＝面積割合の１．５乗）。その結果、表１に示すように試料Ｎｏ．１−１〜Ｎｏ．１−５の磁石素材における磁石相の存在割合は、粉末成形体の相対密度よりも若干多いものの、実質的に等しいことが分かる。   Sample No. 1-1-No. For the magnet material of 1-5, the magnetic phase existence ratio (volume ratio) is obtained by taking a cross-section of the magnet material and performing SEM observation, and converting the area ratio of the magnet phase in the SEM image into a volume ratio (volume ratio). = 1.5 of area ratio). As a result, as shown in Table 1, sample No. 1-1-No. It can be seen that the abundance ratio of the magnet phase in the magnet material of 1-5 is substantially equal, though slightly higher than the relative density of the powder compact.

試料Ｎｏ．１−１０１の樹脂ボンド磁石素材について、磁石相とは、異方性磁石粉末が該当する。従って、試料Ｎｏ．１−１０１の樹脂ボンド磁石素材について、磁石相の存在割合（体積割合）は、｛異方性磁石粉末の体積／（異方性磁石粉末の体積＋樹脂の体積）｝×１００で表されることから、原料に用いた異方性磁石粉末の体積と、樹脂の体積とを用いて算出することができる。   Sample No. With respect to the resin-bonded magnet material 1-101, anisotropic magnet powder corresponds to the magnet phase. Therefore, sample no. For the resin-bonded magnet material 1-101, the abundance ratio (volume ratio) of the magnet phase is represented by {volume of anisotropic magnet powder / (volume of anisotropic magnet powder + volume of resin)} × 100. Therefore, it can be calculated using the volume of the anisotropic magnet powder used as the raw material and the volume of the resin.

その他、樹脂ボンド磁石素材における磁石相の存在割合（体積割合）は、ＪＩＳ Ｋ ７２５０（２００６）「プラスチック−灰分の求め方」に準拠して求めることができる。異方性磁石粉末の体積は、樹脂ボンド磁石素材をマッフル炉にて６００℃に加熱して樹脂を除去し、残った粉末の質量を測定し、この質量を異方性磁石粉末の真密度（ここでは７．５ｇ／ｃｍ３）で除することで求められる。樹脂の体積は、樹脂ボンド磁石素材の質量から異方性磁石粉末の質量を減じて樹脂の質量を求め、この樹脂の質量を樹脂の真密度（ここでは１．２ｇ／ｃｍ３）で除することで求められる。求めた異方性磁石粉末の体積と、樹脂の体積とを上述の式に代入することで、磁石相の存在割合を算出できる。 In addition, the abundance ratio (volume ratio) of the magnet phase in the resin bonded magnet material can be determined according to JIS K 7250 (2006) “Plastics—How to determine ash content”. The volume of the anisotropic magnet powder is determined by heating the resin-bonded magnet material to 600 ° C. in a muffle furnace to remove the resin, measuring the mass of the remaining powder, and determining the mass of the anisotropic magnet powder by the true density ( Here, it is obtained by dividing by 7.5 g / cm 3 ). The volume of the resin is obtained by subtracting the mass of the anisotropic magnet powder from the mass of the resin bonded magnet material to obtain the mass of the resin, and the mass of the resin is divided by the true density of the resin (here 1.2 g / cm 3 ). Is required. By substituting the obtained volume of the anisotropic magnet powder and the volume of the resin into the above formula, the existence ratio of the magnet phase can be calculated.

樹脂ボンド磁石素材における磁石相の存在割合（体積割合）を測定する別の方法として、樹脂ボンド磁石素材の断面を顕微鏡観察し、断面に占める磁石相の面積割合を磁石相の存在割合（体積割合）として用いることが挙げられる。即ち、磁石相の存在割合（体積割合）＝｛（磁石相の面積割合）／（磁石相の面積割合＋樹脂の面積割合）｝×１００とする。具体的には、断面を研磨して、ＳＥＭの反射電子像で観察する。ここで、ＳＥＭ画像では、分子量の大きい磁石相（ここではＮｄ−Ｆｅ−Ｂ合金）と、分子量の小さい樹脂（ここではエポキシ樹脂）とではコントラストが異なる。そのため、コントラスト比を利用して、磁石相の面積割合及び樹脂の面積割合を画像処理によって容易に算出することができる。求めた各面積割合を上述の式に代入することで、磁石相の存在割合を算出できる。なお、樹脂ボンド磁石素材では、磁石相（ここでは異方性磁石粉末）にばらつきがあるため、３個以上の断面をとって、断面ごとに上述のようにして磁石相の存在割合を求めて、その平均を算出することが好ましい。   As another method for measuring the presence ratio (volume ratio) of the magnetic phase in the resin-bonded magnet material, the cross section of the resin-bonded magnet material is observed with a microscope, and the area ratio of the magnet phase in the cross section is determined as the existence ratio (volume ratio) of the magnet phase. ). That is, the existence ratio (volume ratio) of magnet phase = {(area ratio of magnet phase) / (area ratio of magnet phase + area ratio of resin)} × 100. Specifically, the cross section is polished and observed with an SEM reflected electron image. Here, in the SEM image, the contrast is different between the magnet phase having a high molecular weight (here, Nd—Fe—B alloy) and the resin having a low molecular weight (here, epoxy resin). Therefore, using the contrast ratio, the area ratio of the magnet phase and the area ratio of the resin can be easily calculated by image processing. By substituting each obtained area ratio into the above formula, the existence ratio of the magnet phase can be calculated. Since resin-bonded magnet materials vary in the magnet phase (here, anisotropic magnet powder), take three or more cross-sections and determine the abundance ratio of the magnet phase for each cross-section as described above. It is preferable to calculate the average.

作製した試料Ｎｏ．１−１〜Ｎｏ．１−５の磁石素材（バルク体）及び試料Ｎｏ．１−１０１の樹脂ボンド磁石素材を５Ｔのパルス磁界で着磁した後、各試料の磁気特性を調べた。磁気特性は、ＢＨトレーサ（理研電子株式会社製ＤＣＢＨトレーサ）を用いて、残留磁束密度Ｂｒ、磁束密度Ｂと減磁界の大きさＨとの積の最大値、即ち最大エネルギー積（ＢＨ）ｍａｘ（ｋＪ／ｍ３）を調べた。また、以下のようにして配向度を調べた。配向方向に平行な方向の残留磁束密度Ｂｒと、配向方向に直交する方向の二つの残留磁束密度Ｂｒ⊥１、Ｂｒ⊥２とをそれぞれ調べ、Ｂｒの２乗とＢｒ⊥１の２乗とＢｒ⊥２の２乗との和をとり、この和の平方根に対するＢｒの比［Ｂｒ／｛Ｂｒ２＋（Ｂｒ⊥１）２＋（Ｂｒ⊥２）２｝１／２］×１００を算出し、この値を配向度（％）とする。その結果を表１に示す。上記配向方向は、ここでは、成形時の圧縮方向に直交する方向、即ち、成形時の磁場の印加方向に等しく、ｃ軸方向である。上記配向方向に直交する二つの方向はそれぞれ、直交するようにとる。Ｂｒ、Ｂｒ⊥１、Ｂｒ⊥２は、上述のＢＨトレーサを用いて測定した。 The prepared sample No. 1-1-No. 1-5 magnet material (bulk body) and sample no. After 1-101 resin bonded magnet material was magnetized with a 5T pulse magnetic field, the magnetic properties of each sample were examined. The magnetic characteristics are obtained by using a BH tracer (DCBH tracer manufactured by Riken Denshi Co., Ltd.) and the maximum value of the residual magnetic flux density Br, the product of the magnetic flux density B and the magnitude H of the demagnetizing field, that is, the maximum energy product (BH) max ( kJ / m 3 ) was investigated. Further, the degree of orientation was examined as follows. The residual magnetic flux density Br in the direction parallel to the orientation direction and the two residual magnetic flux densities Br ⊥1 and Br ⊥2 in the direction orthogonal to the orientation direction are examined, respectively, and the square of Br, the square of Br ⊥1 and Br. taking the sum of the square of ⊥2, calculates the Br the ratio of the square root of the sum [Br / {Br 2 + ( Br ⊥1) 2 + (Br ⊥2) 2} 1/2] × 100, This value is defined as the degree of orientation (%). The results are shown in Table 1. Here, the orientation direction is equal to the direction orthogonal to the compression direction at the time of molding, that is, the direction in which the magnetic field is applied at the time of molding, and is the c-axis direction. The two directions orthogonal to the orientation direction are each orthogonal. Br, Br 1 and Br 2 were measured using the BH tracer described above.

Figure 2015079925
Figure 2015079925

表１に示すように試料Ｎｏ．１−１〜Ｎｏ．１−５はいずれも、樹脂を含む試料Ｎｏ．１−１０１と比較して、磁石相の含有割合が非常に高いことが分かる。詳しくは、試料Ｎｏ．１−１〜Ｎｏ．１−５はいずれも、磁石相の含有割合が７０体積％以上、更には８０体積％以上であり、多くの試料が８５体積％以上である。また、試料Ｎｏ．１−１〜Ｎｏ．１−５はいずれも、密度が高く、相対密度も高く（ここでは真密度７．５ｇ／ｃｍ３に対して８０％以上）、緻密であるともいえる。このように磁石相の含有割合が高く、緻密になった理由は、塑性変形性に優れる水素化粉末を原料に用いることで、異方性磁石粉末の粒子間を変形した水素化粉末の粒子によって良好に埋められ、かつ変形した水素化粉末の粒子が磁石相に変化したため、と考えられる。 As shown in Table 1, Sample No. 1-1-No. Samples Nos. 1 to 5 containing the resin were sample No. It can be seen that the content ratio of the magnet phase is very high compared to 1-101. Specifically, sample no. 1-1-No. As for 1-5, the content rate of a magnet phase is 70 volume% or more further, Furthermore, 80 volume% or more, and many samples are 85 volume% or more. Sample No. 1-1-No. Each of 1-5 has a high density, a high relative density (here, 80% or more with respect to a true density of 7.5 g / cm 3 ), and can be said to be dense. The reason why the content ratio of the magnet phase is high and dense as described above is that the hydrogenated powder excellent in plastic deformability is used as a raw material, and the particles of the hydrogenated powder deformed between the particles of the anisotropic magnet powder. This is probably because the well-filled and deformed particles of the hydrogenated powder changed to the magnet phase.

また、表１に示すように試料Ｎｏ．１−１〜Ｎｏ．１−５はいずれも、配向度が７０％以上と高く、異方性磁石となっていることが分かる。このように配向性に優れる理由は、結晶磁気異方性を有する異方性磁石粉末を原料に用い、製造過程で異方性磁石粉末を実質的に損傷などしなかったことで、異方性磁石粉末が有する結晶磁気異方性を実質的に維持できたため、と考えられる。換言すれば、実質的に水素化粉末のみが塑性変形したともいえる。また、原料に用いた異方性磁石粉末の配合割合が高いほど、配向度が高くなっていることからも、原料に用いた異方性磁石粉末の磁気特性を実質的に維持でき、その特性を良好に活用できている、と考えられる。   As shown in Table 1, sample No. 1-1-No. As for 1-5, all have orientation degree as high as 70% or more, and it turns out that it is an anisotropic magnet. The reason for such excellent orientation is that anisotropic magnet powder having crystal magnetic anisotropy is used as a raw material, and anisotropic magnet powder is not substantially damaged in the manufacturing process. This is probably because the magnetocrystalline anisotropy of the magnet powder was substantially maintained. In other words, it can be said that substantially only the hydrogenated powder is plastically deformed. In addition, the higher the blending ratio of the anisotropic magnet powder used for the raw material, the higher the degree of orientation, so that the magnetic properties of the anisotropic magnet powder used for the raw material can be substantially maintained, and the characteristics It is thought that is being able to be utilized well.

そして、表１に示すように試料Ｎｏ．１−１〜Ｎｏ．１−５はいずれも、Ｂｒが高く、（ＢＨ）ｍａｘも高いこと、即ち、優れた磁気特性を有することが分かる。例えば、試料Ｎｏ．１−２と、樹脂を含む試料Ｎｏ．１−１０１とを比較すると、試料Ｎｏ．１−２は、原料に用いた異方性磁石粉末が試料Ｎｏ．１−１０１よりも遥かに少ないものの、試料Ｎｏ．１−１０１よりも、Ｂｒ及び（ＢＨ）ｍａｘが高い。このことから、水素化粉末を原料に用いることで、結晶磁気異方性を有する異方性磁石粉末の含有量が少なくても、高い磁気特性を有する希土類磁石が得られるといえる。その他、料Ｎｏ．１−１〜Ｎｏ．１−５はいずれも、磁石相の含有割合が８５体積％程度でありながら、Ｂｒが０．７４Ｔ以上（多くは０．７８Ｔ以上）、（ＢＨ）ｍａｘが９５ｋＪ／ｍ３以上（多くは１００ｋＪ／ｍ３以上）という、高い磁気特性を有することが分かる。 As shown in Table 1, sample No. 1-1-No. It can be seen that 1-5 has a high Br and a high (BH) max, that is, excellent magnetic properties. For example, sample no. 1-2 and sample No. 1 containing resin. In comparison with Sample 1-11, Sample No. 1-2 shows that the anisotropic magnet powder used as a raw material was sample No. Although much less than 1-101, sample no. Br and (BH) max are higher than 1-101. From this, it can be said that by using hydrogenated powder as a raw material, a rare earth magnet having high magnetic properties can be obtained even if the content of anisotropic magnet powder having crystal magnetic anisotropy is small. In addition, fee No. 1-1-No. 1-5 has a magnetic phase content of about 85% by volume, but Br is 0.74 T or more (mostly 0.78 T or more), and (BH) max is 95 kJ / m 3 or more (many is 100 kJ). / M 3 or more).

更に、この試験から、上述のような優れた磁気特性を有する希土類磁石は、原料に異方性磁石粉末と水素化粉末とを用い、磁場成形後に脱水素処理を施すという製造方法によって得られることが確認できた。   Furthermore, from this test, the rare earth magnet having excellent magnetic properties as described above can be obtained by a manufacturing method in which anisotropic magnet powder and hydrogenated powder are used as raw materials and subjected to dehydrogenation after magnetic field forming. Was confirmed.

［付記］
上述の実施形態の希土類磁石の製造方法によって製造される希土類磁石として、例えば、以下の希土類磁石が挙げられる。 [Appendix]
Examples of the rare earth magnet manufactured by the method of manufacturing a rare earth magnet of the above-described embodiment include the following rare earth magnets.

結晶磁気異方性を有する希土類磁石相からなる複数の異方性領域と、
前記異方性領域間に介在され、前記異方性領域の結晶配向度よりも低い結晶配向度を有する希土類磁石相からなる磁性結合領域とを備える希土類磁石。 A plurality of anisotropic regions composed of rare earth magnet phases having magnetocrystalline anisotropy;
A rare earth magnet comprising: a magnetic coupling region comprising a rare earth magnet phase interposed between the anisotropic regions and having a crystal orientation degree lower than that of the anisotropic region.

なお、本発明は、上述した例示に限定されるものではなく、特許請求の範囲によって示され、特許請求の範囲と均等の意味及び範囲内での全ての変更が含まれることが意図される。例えば、上述の試験例１について水素化粉末・異方性磁石粉末の組成・大きさ、異方性磁石粉末の配合割合、異方性磁石粉末の平均結晶粒径、粉末成形体の相対密度、製造条件（成形圧力、印加磁場の大きさ、脱水素条件など）を適宜変更することができる。また、異方性磁石粉末に代えて、残留磁束密度Ｂｒが１．０Ｔ以下、更には０．８Ｔ以下である磁石用粉末を用い、この磁石用粉末と水素化粉末との混合粉末を圧縮成形した後、脱水素処理を施すことで、磁石相の存在割合が高い希土類磁石を製造することができる。   In addition, this invention is not limited to the illustration mentioned above, is shown by the claim, and intends that all the changes within the meaning and range equivalent to the claim are included. For example, for Test Example 1 described above, the composition and size of the hydrogenated powder / anisotropic magnet powder, the blending ratio of the anisotropic magnet powder, the average crystal grain size of the anisotropic magnet powder, the relative density of the powder compact, Manufacturing conditions (molding pressure, magnitude of applied magnetic field, dehydrogenation conditions, etc.) can be changed as appropriate. Further, instead of anisotropic magnet powder, a magnet powder having a residual magnetic flux density Br of 1.0 T or less, further 0.8 T or less is used, and a mixed powder of this magnet powder and hydrogenated powder is compression molded. Then, by performing a dehydrogenation treatment, a rare earth magnet having a high magnet phase ratio can be manufactured.

本発明の希土類磁石の製造方法は、後述する永久磁石などに利用される希土類磁石の製造に利用することができる。本発明の希土類磁石の製造方法によって製造された希土類磁石は、永久磁石、例えば、各種のモータ、特に、ハイブリッド自動車やハードディスクドライブなどに具備される高速モータに用いられる永久磁石に好適である。   The method for producing a rare earth magnet of the present invention can be used for producing a rare earth magnet used for a permanent magnet or the like to be described later. The rare earth magnet manufactured by the method for manufacturing a rare earth magnet of the present invention is suitable for a permanent magnet, for example, a permanent magnet used in various motors, particularly, a high-speed motor provided in a hybrid vehicle, a hard disk drive, and the like.

１ 希土類磁石 １０ 磁石素材 １００ 粉末成形体
１２ 異方性領域 ２０ 異方性磁石粉末 ２１ 異方性磁石粉末の粒子
１３ 磁性結合領域 ３０ 水素化粉末 ３１ 水素化粉末の粒子
３２ 希土類元素の水素化合物 ３４ 鉄族元素を含む相
５０ 金型 ５２ ダイ ５４ 上パンチ ５６ 下パンチ
１１０ 混合粉末 DESCRIPTION OF SYMBOLS 1 Rare earth magnet 10 Magnet raw material 100 Powder molded object 12 Anisotropic area | region 20 Anisotropic magnet powder 21 Particle | grains of anisotropic magnet powder 13 Magnetic coupling | bonding area | region 30 Hydrogenated powder 31 Particle | grains of hydrogenated powder 32 Rare earth element hydrogen compound 34 Phase containing iron group element 50 Mold 52 Die 54 Upper punch 56 Lower punch 110 Mixed powder

Claims (7)

希土類元素の水素化合物と鉄族元素とを含む水素化合金からなる水素化粉末と、希土類元素を含み、結晶磁気異方性を有する異方性磁石粉末とを準備する工程と、
前記水素化粉末と前記異方性磁石粉末とを含む混合粉末を磁場印加中で圧縮成形して粉末成形体を得る工程と、
前記粉末成形体に脱水素処理を施して、前記水素化合金を再結合して、この再結合合金によって前記異方性磁石粉末の粒子が結合された磁石素材を製造する工程とを備える希土類磁石の製造方法。 Preparing a hydrogenated powder comprising a hydrogenated alloy containing a rare earth element hydrogen compound and an iron group element, and an anisotropic magnet powder containing the rare earth element and having crystal magnetic anisotropy;
A step of compression molding a mixed powder containing the hydrogenated powder and the anisotropic magnet powder while applying a magnetic field to obtain a powder compact;
A rare earth magnet comprising: dehydrogenating the powder compact, recombining the hydrogenated alloy, and producing a magnet material in which particles of the anisotropic magnet powder are bound by the recombined alloy. Manufacturing method. 前記希土類元素は、Ｎｄであり、
前記再結合合金は、Ｎｄを含む希土類−鉄系合金である請求項１に記載の希土類磁石の製造方法。 The rare earth element is Nd;
The method of manufacturing a rare earth magnet according to claim 1, wherein the recombination alloy is a rare earth-iron alloy containing Nd. 前記混合粉末における前記異方性磁石粉末の質量割合が５０％超９５％以下である請求項１又は請求項２に記載の希土類磁石の製造方法。   The method for producing a rare earth magnet according to claim 1 or 2, wherein a mass ratio of the anisotropic magnet powder in the mixed powder is more than 50% and not more than 95%. 前記水素化粉末の平均粒径は、３μｍ以上５００μｍ以下である請求項１〜請求項３のいずれか１項に記載の希土類磁石の製造方法。   The method for producing a rare earth magnet according to any one of claims 1 to 3, wherein an average particle diameter of the hydrogenated powder is 3 µm or more and 500 µm or less. 前記異方性磁石粉末は、希土類元素と、鉄族元素と、Ｂ及びＣから選択される少なくとも１種の元素とを含む希土類−鉄系合金からなり、この希土類−鉄系合金の平均結晶粒径が７００ｎｍ以下である請求項１〜請求項４のいずれか１項に記載の希土類磁石の製造方法。   The anisotropic magnet powder is composed of a rare earth-iron alloy containing a rare earth element, an iron group element, and at least one element selected from B and C. The average crystal grain of the rare earth-iron alloy The method for producing a rare earth magnet according to any one of claims 1 to 4, wherein the diameter is 700 nm or less. 前記異方性磁石粉末の平均粒径は、３μｍ以上５００μｍ以下である請求項１〜請求項５のいずれか１項に記載の希土類磁石の製造方法。   6. The method for producing a rare earth magnet according to claim 1, wherein the anisotropic magnet powder has an average particle diameter of 3 μm or more and 500 μm or less. 前記粉末成形体の相対密度が７０％以上である請求項１〜請求項６のいずれか１項に記載の希土類磁石の製造方法。   The method for producing a rare earth magnet according to claim 1, wherein a relative density of the powder compact is 70% or more.
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